Cardiac Disease in Pregnancy D

14 Chapter 2 Cardiac disease in pregnancy D. L. Adamson, M. K. Dhanjal, C. Nelson-Piercy, R. Collis

SYNOPSIS Heart disease and its management in obstetrics Aortic dissection Introduction Ischemic heart disease Physiological changes in pregnancy Arrhythmias Normal ﬁ ndings on examination of the Obstetric anesthetic management of the mother with cardiovascular system in pregnancy cardiac disease Cardiac investigations in pregnancy Anesthetic antenatal assessment and classiﬁ cation Congenital heart disease of mother with cardiac disease Acquired heart disease Anesthetic interventions Endocarditis prophylaxis Anesthetic techniques

Heart disease and its management in obstetrics D. L. Adamson, M. K. Dhanjal, C. Nelson-Piercy

INTRODUCTION disease has continued to rise in the UK since the early 1980s. The major causes of cardiac deaths over Pregnancies complicated by signiﬁ cant heart disease the last 10 years are cardiomyopathy (predominantly are uncommon in the UK, Europe and the devel- peripartum), myocardial infarction (most commonly oped world. However cardiac disease is now the due to coronary artery dissection), dissection of the leading cause of maternal death in the UK. There thoracic aorta and pulmonary hypertension. In were 44 indirect deaths attributed to cardiac disease the UK, rheumatic heart disease is now rare in in 2000-2002, giving a death rate of 2.2 per 100 000 women of childbearing age and mostly conﬁ ned to maternities. The maternal mortality rate from cardiac immigrants.

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Women with congenital heart disease are surviv- increase in cardiac pre-load (such as infusion of ing longer thanks to corrective or palliative surgery fl uids), increase in left atrial and pulmonary venous in childhood. They are therefore not uncommonly pressure (such as in mitral stenosis) or increased encountered in pregnancy. These women may have pulmonary capillary permeability (such as in pre- complicated pregnancies. Women with mechanical eclampsia), or a combination of these factors. prosthetic valves face diffi cult decisions regarding In late pregnancy in the supine position, pressure anticoagulation in pregnancy. of the gravid uterus on the inferior vena cava causes Because of signifi cant physiological changes in a reduction in venous return to the heart and a con- pregnancy, symptoms, such as palpitations, and signs sequent fall in stroke volume and cardiac output. such as an ejection systolic murmur are very common Turning from the lateral to the supine position may innocent fi ndings. Not all women with signifi cant result in a 25% reduction in cardiac output. Pregnant heart disease are able to meet these increased physio- women should therefore be nursed in the left or right logical demands. The care of the pregnant and lateral position wherever possible. If the mother has parturient woman with heart disease requires a mul- to be kept on her back, the pelvis should be rotated tidisciplinary approach, involving obstetricians, car- so that the uterus drops to the side and cardiac output diologists and anesthetists, preferably in a dedicated as well as uteroplacental blood fl ow are optimized. antenatal cardiac clinic. This allows formulation of an Reduced cardiac output is associated with a reduction agreed and documented management plan encom- in uterine blood fl ow and therefore in placental per- passing management of both planned and emergency fusion; this can compromise the fetus. delivery. Labor is associated with further increases in cardiac output (15% in the fi rst stage and 50% in the second stage). Uterine contractions lead to autotransfusion of 300-500 mL of blood back into the circula- PHYSIOLOGICAL CHANGES tion and the sympathetic response to pain and IN PREGNANCY anxiety further elevate heart rate and blood pressure. Cardiac output is increased more during contractions Blood volume starts to increase by the fi fth week after but also between contractions. The rise in stroke conception secondary to estrogen- and prostaglandin- volume with each contraction is attenuated by good induced relaxation of smooth muscle that increases pain relief and further reduced by epidural analgesia the capacitance of the venous bed. Plasma volume and the supine position. Epidural analgesia or anes- increases and red cell mass rises but to a lesser degree, thesia cause arterial vasodilation and a fall in blood thus explaining the physiological anemia of preg- pressure. General anesthesia is associated with a rise nancy. Relaxation of smooth muscle on the arterial in blood pressure and heart rate during induction, side results in a profound fall in systemic vascular but cardiovascular stability thereafter. Prostaglan- resistance and together with the increase in blood dins given to induce labor have little effect on volume, determines the early increase in cardiac hemodynamics but ergometrine causes vasocons- output. Blood pressure falls slightly but by term has triction and syntocinon can cause vasodilation and usually returned to the pre-pregnancy value. The fl uid retention. increased cardiac output is achieved by an increase in Following delivery of the baby up to 1 L of blood stroke volume and a lesser increase in resting heart may be returned to the circulation due to the relief of rate of 10-20 beats/min. By the end of the second tri- inferior vena cava obstruction and contraction of the mester the blood volume and stroke volume have uterus. The intrathoracic and cardiac blood volumes risen by between 30 and 50%. This increase correlates rise, cardiac output increases by 60-80% followed by with the size and weight of the products of conception a rapid decline to pre-labor values within about 1 h and is therefore considerably greater in multiple of delivery. Transfer of fl uid from the extravascular pregnancies as is the risk of heart failure in heart space increases venous return and stroke volume disease. further. Those women with cardiovascular compro- Although there is no increase in pulmonary capil- mise are therefore most at risk of pulmonary edema lary wedge pressure (PCWP), plasma colloid oncotic during the second stage of labor and the immediate pressure is reduced. The colloid oncotic pressure- postpartum period. All the changes revert quite pulmonary capillary wedge pressure gradient is rapidly during the fi rst week and more slowly over reduced by 28%, making pregnant women particu- the following six weeks but even at a year signifi cant larly susceptible to pulmonary edema. Pulmonary changes still persist and are enhanced by a subse- edema may be precipitated if there is either an quent pregnancy.

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NORMAL FINDINGS ON EXAMINATION a lesion which is associated with long-term survival OF THE CARDIOVASCULAR SYSTEM or because they have had successful surgery. Whilst IN PREGNANCY some may not be able to tolerate the hemodynamic changes of pregnancy, the majority will have enough Normal fi ndings on cardiovascular examination may cardiac reserve to carry a pregnancy to term. CHD is include a loud fi rst heart sound with exaggerated infrequently associated with maternal mortality, splitting of the second heart sound and a physiological however, there may be a signifi cant deterioration in third heart sound at the apex. A systolic ejection the maternal condition. These complex patients should murmur at the left sternal edge is heard in nearly all be jointly cared for by obstetricians, obstetric physi- women and may be remarkably loud and be audible cians and cardiologists with expertise in pregnancy all over the precordium. It varies with posture and if and adult congenital heart disease and provide a chal- unaccompanied by any other abnormality it refl ects lenge for such a team. the increased stroke output. Venous hums and mam- mary souffl es may be heard. Because of the peripheral vasodilation the pulse may be bounding and in addi- Pre-pregnancy counseling and assessment tion ectopic beats are very common in pregnancy. Most women with congenital heart disease are known to a cardiologist prior to pregnancy. It is extremely CARDIAC INVESTIGATIONS important that such women are appropriately coun- IN PREGNANCY seled about their individual health risks with pregnancy. If pregnancy carries an unacceptable risk, this The electrocardiographic (ECG) axis shifts superiorly should be explained and appropriate contraceptive in late pregnancy due to a more horizontal position of advice given. Advising an individual may be diffi cult, the heart. Small Q-waves and T-wave inversion in the particularly those with corrected complex disease, as right precordial leads are not uncommon. Atrial and data remain sparse for pregnancy outcomes following ventricular ectopics are both common. some forms of corrective and palliative surgery. The amount of radiation received by the fetus Maternal risk of pregnancy is assessed by obtain- during a maternal chest X-ray (CXR) is negligible and ing an accurate history, which will defi ne the func- a CXR should never be withheld if clinically indicated tional status, examination and undertaking relevant in pregnancy. Transthoracic echocardiogram is the investigations. This also provides a baseline of the investigation of choice to exclude, confi rm or monitor cardiovascular status, allowing any change occurring structural heart disease in pregnancy. Transesopha- in pregnancy to be objectively assessed. It may be geal echocardiograms (TEE) are also safe with the necessary to treat the woman prior to pregnancy in usual precautions to avoid aspiration. Magnetic order to minimize risk. resonance imaging (MRI) and CT pulmonary angio- Poor maternal functional class (see Table 2.1), cya- graphy are considered safe in pregnancy (see Ch. 21). nosis, history of transient ischemic attack (TIA), heart Routine investigation with electrophysiological failure, left arrhythmia, left heart outfl ow obstruction studies and angiography are normally postponed and impaired ventricular function have all prospec- until after pregnancy but angiography should not be tively been found to be associated with poor maternal withheld if required, for example in acute coronary outcome. Maternal cyanosis is also a risk factor for syndromes. fetal and neonatal complications. There is only a 12% likelihood of a live birth if the resting arterial saturation is ≤ 85% whilst ≥ 85% is associated with a 63% CONGENITAL HEART DISEASE likelihood of a live birth. Most CHD is inherited in a multifactorial manner, Congenital heart disease (CHD) in adults is increas- however single gene disorders, chromosome abnor- ing in frequency as a result of the success of congenital malities and maternal disease can be the cause. The cardiology and cardiac surgery. It is the commonest risk of recurrent CHD is summarized in Table 2.2. The birth defect with just under 1% of newborns having risk of cardiac malformation secondary to maternal CHD. Half the CHD population are women, and are diabetes mellitus is approximately 2-3%, while in usually well enough to contemplate and undergo single gene or chromosomal abnormalities such as pregnancy. The majority of women with CHD who Marfan, Noonan and Holt-Oram syndromes the risk reach childbearing age do so because they either have of inherited heart disease is 50%.

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Table 2.1 New York Heart Association (NYHA) causing right ventricular overload and dilatation. If functional classifi cation small or corrected, they cause no specifi c or signifi - cant problems during pregnancy and do not require Class Description antibiotic prophylaxis (Table 2.3). In an uncorrected I No breathlessness/uncompromised defect, the effect of an increase in cardiac output on a II Breathlessness on severe exertion/slightly volume-loaded right side is counterbalanced by the compromised decrease in peripheral vascular resistance. The two III Breathlessness on mild exertion/moderately main areas of concern are paradoxical embolus or compromised arrhythmia. The former is rare but if the pregnant IV Breathlessness at rest/severely woman is immobilized or has other risk factors for compromised thrombosis, thromboembolic prophylaxis is advised. The risk of atrial arrhythmias is well established with ASDs and remains even with correction. These should be treated dependent upon the rhythm (see arrhythmia section). Table 2.2 Risk of congenital heart disease in a future VSDs are less common and often corrected in child- pregnancy hood, unless they are small and hemodynamically insignifi cant. The only risk is that of endocarditis and Risk of CHD in future prophylaxis is advised for delivery (see Table 2.3). Risk factor pregnancy (%) One previous child with CHD 2 Valve disease Two previous children with CHD 10 Mother with CHD 6 While all valves can be congenitally affected, the com- Father with CHD 2 monest lesion is that of a bicuspid aortic valve leading to aortic stenosis. This results in a fi xed cardiac output. The majority of young women are asymptomatic and pregnancy is likely to be tolerated well. It is important The mode of delivery may also require some to assess these women prior to pregnancy to deter- consideration prior to conception, although events in mine whether it would be safer undergoing a preg- pregnancy may infl uence this. Cardiologists in the nancy with the native valve or whether surgery should past have traditionally favored a Cesarean section be contemplated prior to conception. Pregnancy is (CS). In the majority of cases, however, vaginal deliv- likely to be well tolerated if: ery is safest for the mother. In comparison to CS, 1. Resting ECG has no ST segment depression. vaginal delivery is associated with a reduction in both 2. On exercise testing, there is an appropriate blood loss and thromboembolic risk. There are also increase in BP and HR and no ST change. less abrupt hemodynamic changes, particularly when 3. The pressure across the aortic valve measures less assisted by effective analgesia and a short second than 80 mmHg at peak and mean pressure stage of labor. Vaginal delivery has to be balanced gradient is less than 50 mmHg. against the lack of predictable delivery time where a 4. There is good LV f u nct ion team can be prepared for all eventualities. Absolute indications for CS are Marfan syndrome with an aortic Women should be monitored throughout preg- root dilated beyond 4.5 cm, aortic aneurysm and an nancy to identify symptoms and signs suggestive of acutely unwell mother. decompensation, such as an exaggerated tachycardia or dyspnea, angina, pulmonary edema or new ECG Acyanotic heart disease changes. A fall in pressure gradient across the aortic Septal defects valve is suggestive of a reduction in LV function. Women with symptomatic aortic stenosis should be Atrial septal defects (ASD) are the most common con- managed with bed rest to prevent the requirement genital lesions found in adults, making up between of an increased cardiac output, and beta blockade 10-17%, while ventricular septal defects (VSD) are the which reduces cardiac output as well as lengthening commonest form in children (1.5-3.5 per 1000 live diastole to aid coronary fi lling. In extreme cases of births). ASDs are often left uncorrected unless there decompensation, emergency balloon aortic valvot- is either a large hole or signifi cant left to right shunt omy or aortic valve replacement can be considered

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Table 2.3 Risk of infective endocarditis with different cardiac conditions

Degree of risk of infective Prophylaxis endocarditis required Cardiac condition High Yes Previous bacterial endocarditis Prosthetic heart valves or other foreign material Surgically created systemic or pulmonary conduits Complex cyanotic congenital heart diseases Moderate Yes Acquired valvular heart disease MVP with MR or severe valve thickening Non-cyanotic congenital heart diseases (except secundum type ASD) including bicuspid aortic valves Hypertrophic cardiomyopathy Negligible No Isolated secundum/sinus venosus ASD Surgically repaired ASD, VSD, PDA (provided no left valve abnormalities) MVP without regurgitation Physiological heart murmurs Cardiac pacemakers Pulmonary valve stenosis and post-operative valvotomy Total anomalous pulmonary drainage Well repaired tetralogy of Fallot with no shunts, aortic regurgitation, or valve grafts

but are associated with signiﬁ cant maternal and fetal Congenitally corrected transposition of the morbidity and mortality. Where the woman has pro- great arteries gressed well through pregnancy, a vaginal delivery can be considered but hypovolemia and vasodilators In this condition the ventricles are switched round, i.e. should be avoided. Some women with bicuspid the right atrium drains into the left ventricle which is aortic valves have post stenotic dilatation of the aorta positioned where the right ventricle should be and and as such are at risk of aortic dissection. A history then it drains back out into the pulmonary artery. De- of chest pain should thus be taken extremely oxygenated blood is still directed to the lungs, and seriously. oxygenated blood to the body. However, the morpho- logical right ventricle now has to support a systemic circulation and pressure, which it is not designed to Aortic pathology do. Additionally, the tricuspid valve between the left sided atrium and ventricle is prone to regurgitation The commonest problems encountered are aortic dis- in this higher-pressure system. If patients are well section (see later) and coarctation of the aorta. and have no deterioration in right (systemic) heart Although women with aortic coarctation have usually function, they will probably tolerate pregnancy well. undergone corrective surgery prior to pregnancy, re- However, right heart function as well as systemic tri- coarctation or aneurysm formation at the site of cuspid atrioventricular valve regurgitation may dete- surgery can occur. The aorta should therefore be riorate in pregnancy. Finally, the atrioventricular node assessed prior to conception or as early in pregnancy is absent and thus patients often have heart block as possible, preferably with MRI. If there is no signiﬁ - requiring pacing. cant defect, then a woman should be able to undergo a vaginal delivery with a short second stage. Patients Hypertrophic cardiomyopathy with coarctation or aneurysm should have aggressive blood pressure management to minimize the risk of This condition, previously thought to be rare, may dissection (see aortic dissection). Pregnancy is usually affect up to 2 in 1000 people. Up to 70% of cases are well tolerated by all groups and mortality is low. familial with autosomal dominant inheritance. The

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diagnostic criteria for hypertrophic cardiomyopathy Women with PH should be strongly advised against (HCM) are unexplained asymmetrical myocardial pregnancy and adequate contraception is imperative. hypertrophy on echocardiography. Diagnosis is The subdermal progestogen implant Implanon® is the usually made as the result of echocardiography to most suitable contraceptive in view of its effectiveness investigate symptoms, a heart murmur or as part of and lack of cardiovascular risk. It is more effective familial screening. than sterilization, which requires a general anesthetic. Many women encountered in pregnancy are It can be inserted even with those on warfarin. If the asymptomatic. Clinical features do not relate to the patient is on the enzyme inducer Bosentan which degree of left ventricular outfl ow tract obstruction renders Implanon® less effective, oral progestagen- and include chest pain, breathlessness, pre-syncope, only oral contraception should be added. IUCDs are syncope, atrial or ventricular arrhythmias, heart usually best avoided due to the risk of a vagal response failure and sudden death. The overall risk of disease- with cervical dilatation. related complications such as sudden death, endstage Women with PH who do become pregnant should heart failure, and fatal stroke is roughly 1-2% per year. be advised of the high risk of mortality and termina- Risk factors for sudden death include a positive family tion of pregnancy advised. Termination of pregnancy history with 2 or more sudden cardiac deaths at < 40 can be performed medically or surgically depending years (as the risk of sudden cardiac death may be on facilities available. A medical termination can be increased in certain genotypes), abnormal blood pres- performed at any gestation using mifepristone and sure response to exercise (failure of systolic blood then misoprostol or gemprost. The disadvantages are pressure to rise by > 25 mmHg from baseline values) that it may take several days to complete during which and ventricular tachycardia. Most sudden deaths there may be signifi cant pain and bleeding. This can occur in patients with left ventricular wall thickness result in a tachycardia that may not be tolerated well. less than 30 mm, so the presence of mild hypertrophy Adequate analgesia is essential. The procedure should cannot be used to reassure patients that they are at be performed in a high dependency area with full low risk. monitoring. Expulsion of the products of conception There are case reports of sudden death in preg- or delivery of the fetus can be unpredictable. Products nancy in patients with HCM however large series of conception may be retained requiring surgical report few problems with pregnancy in patients with evacuation. HCM. It is thought that deaths recorded may refl ect Surgical termination can be performed by suction, the background expected rate and pregnancy seems or at gestations over 13 weeks, by dilatation and evac- not to be associated with an increased risk. uation. Both procedures can be planned with appro- In pregnancy, beta-blockers should be commenced priate medical staff available. The risks of a vagal in women with symptoms. Caution is needed with response, uterine perforation and bleeding are reduced regional anesthesia/analgesia since vasodilation may with skilled operators. be poorly tolerated. Any hypovolemia or blood loss If women decline termination of pregnancy, they should be aggressively corrected and the patient kept require careful management with a multidisciplinary ‘well fi lled’ during labor and delivery. Asymptomatic team with expertise in PH. Bosentan has been shown HCM is not an indication for Cesarean section and to be teratogenic in the fi rst trimester in animal most of these women may deliver in their local units. studies, but it continued use may be necessary for maternal health. Prophylactic heparin throughout the Cyanotic heart disease pregnancy and elective admission for bed rest and Cyanotic heart disease with oxygen therapy (which acts as a vasodilator) from 20- pulmonary hypertension 24 weeks’ gestation onwards are usually recommended. Most women with Eisenmenger’s syndrome Eisenmenger’s syndrome is a broad term applied to who die as a result of pregnancy, do so soon after any cardiac anomaly in which the pathological process delivery. There is no evidence that Cesarean versus of increased pulmonary fl ow leads to obliterative pul- vaginal delivery, nor regional versus general analge- monary vascular disease. The result is pulmonary sia/anesthesia reduces this risk. The dangers relate to hypertension (PH), which is severe enough to reverse increasing the right-to-left shunt and escalating pul- the left-to-right shunt to right-to-left. The PH is usually monary hypertension often despite intensive and irreversible even after corrective surgery. Pulmonary appropriate care. The principles of management hypertension of any cause carries a 40-50% risk of include multidisciplinary discussion and planning of maternal death even if pulmonary pressures are only elective delivery. Postpartum management should half of systemic. be in an intensive care environment by intensivists,

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anesthetists, cardiologists and obstetricians. Supple- Post surgical correction mental oxygen reduces pulmonary vascular resistance. It is important to avoid hypovolemia and The majority of women who have had defi nitive acidosis, maintain pre-load, continue thrombopro- correction of simple lesions such as ASD, VSD, patent phylaxis and avoid pulmonary artery catheters, which ductus arteiosus (PDA) can be treated as normal carry a risk of potentially devastating in situ throm- provided there is no signifi cant residual lesion. bosis. Systemic vasodilators (nitrates, epidural anes- The increased risk of arrhythmias, particularly atrial thesia and syntocinon) should be avoided but selective arrhythmias remains. In normal pregnancy, right ven- pulmonary vasodilators, e.g. inhaled nitric oxide, i.v. tricular volumes increase and this may lead to prob- prostacyclin, sildenafi l and the endothelin antagonist lems in women with right ventricular dysfunction. bosentan may be helpful although many women die The more complex procedures, particularly those with despite optimal use of these measures. shunts are prone to specifi c complications and are discussed below. Cyanotic heart disease in the absence of pulmonary hypertension Repaired tetralogy of Fallot In complex cyanotic heart disease without PH mater- Despite the complexity of the original lesion, a suc- nal risk is dependent upon: cessful correction is likely to lead to an uncomplicated successful pregnancy. One report of 40 pregnancies in 1. Ventricular function (see Table 2.1). 27 women demonstrated no serious complications in 2. Hemorrhage due to impaired clotting factors and any of the pregnancies and an incidence of miscar- platelet function. riage comparable to that of the general population. A 3. Paradoxical embolus as all cyanotic patients shunt second report of 63 pregnancies in 29 women reported from right to left. that 13 ended in termination and 6 pregnancies were 4. Heart failure. complicated by arrhythmias and/or right sided heart 5. Increasing cyanosis secondary to the vasodilata- failure. tion of pregnancy. These women require assessment to confi rm that Cyanosis is associated with adverse effects on the there is no signifi cant right ventricular outfl ow fetus with an increased incidence of low birth weight, obstruction, pulmonary regurgitation (PR) or reduc- prematurity and fetal loss (see Table 2.4). tion in right ventricular function. The PR may get These patients need careful monitoring in a unit worse as the pregnancy progresses causing increasing that understands the complex physiology of the mater- tiredness and breathlessness which is best treated nal circulation. Women often require bed rest and with bed rest and diuretics. oxygen which may reduce cyanosis and, as such, improve fetal well-being. Repaired transposition of the While spontaneous vaginal delivery is best for the great arteries mother, fetal growth restriction or fetal distress often precipitates a Cesarean section. It is important in these The Mustard operation uses a baffl e (conduit) to direct situations to maintain the circulatory volume and pulmonary venous return into the right ventricle and avoid signifi cant vasodilation. The use of aspirin in transposed aorta, and the systemic venous blood via these women is controversial because of the increased the mitral valve and left ventricle. Essentially, this bleeding risk associated with poor platelet function. allows blood to go in the right direction but through the wrong ventricle. Therefore the right ventricle and tricuspid valve support the systemic circulation with the same problems as in congenitally corrected trans- Table 2.4 Livebirth rates with varying degrees of position (see above). maternal cyanosis The Senning operation is physiologically the same as the Mustard. The difference is that with the Senning, Maternal oxygen saturation (%) Livebirth rate (%) the baffl e is created from right atrial wall and atrial >90 92 septal tissue whilst the Mustard creates the baffl e ≥85–90 63 using pericardium or synthetic material. <85 12 The Rastelli repair operation uses a valved conduit for certain complex congenital lesions including

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transposition with pulmonary stenosis. Women with have an arrhythmia. A CXR will show an enlarged either subaortic stenosis or residual conduit obstruc- heart and pulmonary edema. The ECG confi rms a tion can develop greater obstruction in pregnancy. tachycardia with possible atrial or ventricular arrhyth- The main complication from repaired transposi- mias, the signs of either left heart strain (ST depres- tion of the great arteries is narrowing of the pulmo- sion and T-wave inversion in the chest leads) or left nary venous pathway because of the baffl e structure. bundle branch block (LBBB). Complications include This fi xed obstruction acts as a physiological equiva- renal and hepatic dysfunction from low cardiac lent of mitral stenosis. These women require com- output, life threatening pulmonary edema, systemic plete assessment before or early in pregnancy. or pulmonary emboli from mural thrombus, fatal However, providing the right ventricular function is arrhythmias and death. good, pregnancy is usually well tolerated. The diagnosis is made with the temporal relation- ship with pregnancy and echocardiography which Post-Fontan procedure shows increased cardiac dimensions, left ventricular systolic dysfunction often with global/biventricular The Fontan circulation was developed for patients involvement (left ventricular ejection fraction < 45%; with a functional single ventricle. The single ventricle fractional shortening < 30% in M-mode; left ventricu- supports the systemic circulation while the systemic lar end-diastolic dimension > 2.7 cm/m2; and dilata- venous return is directed to the pulmonary artery tion, often of all four chambers). directly through a baffl e. This means there is no pump directing the blood through this shunt. While this repairs any shunts and thus abolishes cyanosis, the Management circulation is prothrombotic, has a limited ability to increase cardiac output and poorly tolerates atrial Treatment is supportive as the underlying condition arrythmias and hypovolemia. However, in those can only be treated with delivery. Pulmonary women with good ventricular function and few symp- edema should be treated by sitting the patient up, toms, pregnancy may be well tolerated. giving oxygen, diamorphine and loop diuretics. Vasodilators such as nitrates, isosorbide or hydrala- ACQUIRED HEART DISEASE zine will help reduce afterload. These can be replaced with ACE inhibitors postpartum, which may also Peripartum cardiomyopathy help with cardiac remodeling. Thromboprophylaxis is essential and low molecular weight heparin Peripartum cardiomyopathy (PPCM) is a rare illness (LMWH) such as enoxaparin is valuable. A higher where there is an onset of heart failure with no iden- dose may be required particularly in those with tifi able cause in the last month of pregnancy or within associated arrhythmias. In such cases warfarin the fi rst 5 months postpartum, in the absence of heart should be used postnatally and breast feeding disease before the last month of pregnancy. It is asso- can continue. Digoxin can be safely used for atrial ciated with increased maternal age, Afro-Caribbean fi brillation or fl utter and beta-blockers may be used race, multiparity, multiple pregnancy and hyperten- with caution for rate control in those with preserved sion. It is similar in its clinical presentation to cardiac output. dilated cardiomyopathy, but the latter is not related In many cases preterm delivery will be iatrogenic to pregnancy. due to maternal cardiac deterioration. Caution should be used with the administration of steroids for fetal Clinical features lung maturation in such cases as further fl uid overload can occur. A pre-emptive increase in diuretics Presentation varies from an incidental fi nding during may prevent sudden deterioration. echocardiography through to severe heart failure and In the patient who remains hypoxic and hypoten- death. Cardiac decompensation in an otherwise stable sive, intubation, ventilation and inotropic support is patient may occur with iatrogenic fl uid or syntocinon necessary. Delivery by Cesarean section will assist in infusions, beta-agonists for tocolysis and steroids reducing the cardiac requirement. Occasionally an for fetal lung maturity, which may all cause fl uid intra-aortic balloon pump or a left ventricular assist overload. device may be needed in the interim until myocardial Clinically the patient may be tachycardic and recovery occurs or until cardiac transplantation is tachypneic with congestive cardiac failure and may performed.

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Delivery Subsequent pregnancy Vaginal delivery is appropriate in those who have Such women should have pre-pregnancy counseling relatively mild disease or in those who are adequately where the risk of cardiac decompensation and mater- treated. Invasive monitoring in labor is recommended nal death should be discussed frankly. with arterial and central venous lines. Pulmonary In those with persistent LV dysf u nct ion or dilata- wedge pressure readings are not usually necessary. tion 6 months after the initial diagnosis of PPCM, Elevations in central venous pressure (CVP) should pregnancy should be actively discouraged as the risk be treated with diuretics. Intravenous beta-blockers of worsening heart failure is 50% and maternal such as metoprolol may be required for tachycardia. death 25%. Adequate contraception should be used However extreme caution must be used because of such as the intra-uterine progestogen-only system or their negative inotropic effect. They should be avoided the subdermal progestogen-only implant. in women in frank pulmonary edema. Analgesia in It is diffi cult to predict the outcome of a subsequent the form of an epidural needs to be administered pregnancy in those whose LV function returns to with due care and consultant anesthetic involvement normal. The contractile reserve may be diminished is imperative. and this may only become apparent with the hemo- Induction of labor is often considered in such dynamic stress of a future pregnancy. A study using patients to allow for insertion of lines, and to plan for modifi ed dobutamine stress echocardiography has all relevant senior staff to be available for labor and shown that women who have ‘recovered’ with normal delivery. Often patients are on twice daily LMWH LVEF on sta ndard echocardiography have impaired preparations, and induction of labor allows the contractile reserve suggesting an increased risk of heparin dose to be omitted prior to the onset of labor, deterioration in a future pregnancy. There will be a thereby allowing the use of regional anesthesia which few women who will tolerate another pregnancy, but is very useful for pain control and hence prevention it is currently not possible to identify this group. of maternal tachycardia. Approximately 20% will develop cardiac failure. In the event of an obstetric indication, or if If the cardiac function has returned to normal and there is signifi cant maternal compromise or severe the woman wishes to embark on another pregnancy, disease, a Cesarean section should be performed. she should have full hospital combined obstetric and Delivery should be planned and is often carried out cardiology care. A baseline echocardiogram should be in operating theatres with access to cardiothoracic performed. At booking it is essential to ensure that facilities. teratogenic medications are discontinued and replaced A dilute infusion of 5 units of syntocinon is used as necessary. If the pregnancy is unplanned consider- for the third stage. In the event of a postpartum hem- ation should be given to termination. Echocardiogra- orrhage, ergometrine can be used. Misoprostol is phy should be arranged at regular intervals. If clinical useful as an effi cient uterine contractor. Thrombopro- or echocardiographic deterioration occurs, serious phylaxis should be continued postpartum when there consideration should be given to discontinuation of are no bleeding concerns. the pregnancy either as a termination of pregnancy or as a preterm delivery.

Prognosis Other dilated cardiomyopathies There is a highly variable outcome that may not always These may be idiopathic or related to other conditions be predicted by the initial severity of the left ventricu- such as SLE (see Table 2.5). Women with known lar systolic dysfunction or dilatation. Patients may impaired LV function from any cause have high-risk improve with treatment and return to normal (50%), pregnancies because they may be unable to meet the improve slowly and be left with a degree of LV impair- demands for an increased cardiac output and deterio- ment which may over years improve, or may deterioration in LV function may occur in pregnancy. In rate despite full medical intervention and require patients with idiopathic dilated cardiomyopathy heart transplant. Cardiomyopathy is the cause of (DCM) outside pregnancy, their three-year survival almost a quarter of cardiac maternal deaths. In one falls from 92% in patients with an ejection fraction of study, the ﬁ ve-year survival was 94% but data from greater than 40% to 71% in patients with an ejection this study are likely to be over-reassuring as half of fraction of less than 30%. These risks are higher than the patients with a diagnosis of PPCM had myocardi- the mortality risk from peripartum cardiomyopathy. tis on endomyocardial biopsy. Pregnancy is contraindicated if the patient is New

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Table 2.5 Causes of dilated cardiomyopathy will reduce the time for fi lling of the left ventricle in diastole, and results in further increases in left atrial Group Examples pressure. Thus a vicious circle is begun, ultimately Infections Viral, e.g. coxsackie B, HIV, Ebstein– causing pulmonary edema and PH. Left atrial dilata- Barr virus, varicella, echovirus, tion predisposes to atrial arrythmias. measles, mumps, polio Deterioration in pregnancy may occur due to a Other: bacterial, e.g. TB; rickettsia; number of factors including the physiological increase parasites; fungi in vascular volume that is maximal at around 20-24 Neuromuscular Muscular dystrophies weeks gestation, autotransfusion after delivery of Nutritional Niacin, thiamine, selenium defi ciencies, the placenta, iatrogenic fl uid infusions, or related to defi ciencies Kwashiorkor further tachycardia which may be due to pain at Connective tissue Rheumatoid arthritis, systemic lupus delivery, exercise, anxiety, intercurrent infection or diseases erythematosus, dermatomyositis arrythmias. Vascular Kawasaki disease Pre-pregnancy advice This is essential for women Hematological Thalassemia, sickle cell disease, iron with valvular heart disease. It allows for a defi ciency anemia full cardiological clinical and echocardiographic Drugs Alcohol, chloroquine, iron overload, assessment prior to embarking on pregnancy. The cyclophosphamide following points should be considered Endocrine Hypo- and hyperthyroidism, 1. Is surgical or interventional treatment of valve hypoparathyroidism, lesions required pre-pregnancy to optimize phaeochromocytoma maternal and fetal well-being in pregnancy? Metabolic Hemochromatosis, glycogen storage 2. Is adaptation of potentially teratogenic diseases medication required prior to pregnancy? 3. Is pregnancy contraindicated?

York Heart Association (NYHA) grade 3-4 (see Pregnancy is absolutely contraindicated in women Table 2.1) or if Left Ventricular Ejection Fraction with associated PH, and those with two or more risk (LVEF) is less than 30%. factors (see below), due to maternal death rates of 30- 60%. Fetal and neonatal risks are also higher. Such Acquired valvular heart disease women should be given adequate contraception such as a subcutaneous progesterone implant. Mitral valve prolapse Assessment of the degree of cardiac compromise This is predominantly a benign condition that should should be made in the remainder. Those women not cause concern in pregnancy. An echocardiogram exhibiting any of the risk factors below should be should be performed to exclude mitral regurgitation. advised of the higher rates of adverse maternal events If present, antibiotic prophylaxis against bacterial including pulmonary edema, sustained brady- or endocarditis is required (see Table 2.8). tachyarrythmias requiring treatment, stroke, cardiac arrest or death: Rheumatic heart disease • Reduced left ventricular systolic function with ejection fractions of < 40%. In young women most cases of acquired valvular Left heart obstruction – aortic or mitral heart disease are due to rheumatic heart disease, or • stenosis with valve areas of < 1.5 cm2 or < 2.0 cm2, previous endocarditis. Of these, mitral stenosis is the respectively. most common and potentially the most likely to cause Previous cardiovascular events including maternal and fetal compromise. • heart failure, transient ischemic attacks or stroke. Stenotic heart lesions • Reduced functional capacity: disease of NYHA In mitral stenosis, the restriction in outﬂ ow from the class II or higher (see Table 2.1). left atrium results in higher left atrial pressures, left atrial enlargement and eventually right sided heart The absolute risks of these adverse events are 4% failure. The reduced blood to the left ventricle causes in women with no risk factors, 27% with one and 62% stroke volume to be reduced. A compensatory tachy- with two or more risk factors. The fetal and neonatal cardia occurs to maintain cardiac output. This however risks (preterm delivery, intrauterine growth restric-

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tion, respiratory distress syndrome, intraventricular eliminates the need for radiation. There is a 1% risk hemorrhage and death) are increased in those with of major complications with this procedure which left heart obstruction and NYHA class II or higher include dislodging of thrombi, cracking of a stenotic disease. valve resulting in regurgitation which may be severe Surgical intervention with either balloon valvulo- enough to require immediate valve replacement, and plasty or valve replacement pre-conception (especially death. Comparatively, closed mitral valvotomy has a if NYHA class III or IV, or mitral valve area < 1 cm2), 3% maternal complication rate, which rises to 5% will change the risk factor profi le, allowing many with open valvotomy. Fetal mortality is 5-15% with of these women to undergo a relatively less compli- closed valvotomy increasing threefold if the proce- cated future pregnancy and labor than those treated dure is open. The success of open valve replacements medically. in pregnancy for severe mitral stenosis is similar to Women should be advised to give up smoking and the non pregnant state, but the stillbirth rate is to start folic acid preconceptionally. 10-30%. Booking visit Arrangements should be made for Delivery Antibiotic prophylaxis should be full hospital care with combined obstetric and cardio- administered to prevent bacterial endocarditis (see logical input. A baseline echocardiogram, ECG and Table 2.8). U+E should be performed. The ECG may show right Vaginal delivery should be the aim unless there axis deviation and P mitrale. is an obstetric indication for Cesarean section. The If the pregnancy is unplanned, detailed assessment ‘cardiac position’ is best adopted with the legs lower of functional capacity, left ventricular function, degree than the abdomen. Lithotomy and supine positions of valvular obstruction and history of heart failure should be avoided. An epidural will provide ade- or embolic events should be made to see whether quate analgesia and will allow an instrumental the pregnancy can continue or termination should be delivery to be performed in the second stage. Those advised. with moderate or severe mitral stenosis should Antenatal care A combined assessment with a ideally have invasive monitoring with an arterial cardiologist or obstetric physician should be made line and CVP. Critical mitral stenosis may require each trimester at least, and more frequently if clinical pulmonary arterial (PA) catheterization though this deterioration occurs. Although routine echocardiog- has to be balanced with the risks of leaving a cathe- raphy is unnecessary, it should be performed if there ter in the PA in a pro-thrombotic patient. Pushing is any change in function. causes rises in the heart rate that may not be toler- With mitral stenosis, the heart rate should be con- ated and hence assisted vaginal delivery is often trolled with beta-blockers which will allow more performed. fi lling of the left ventricle in diastole and hence reduces A dilute infusion of syntocinon should be admin- the already elevated pressure in the left atrium. The istered for the third stage (see peripartum cardiomy- benefi ts of this far outweigh the small risk of fetal opathy). A degree of blood loss is tolerated well as it growth restriction with beta-blockers. is the autotransfusion just after delivery which often The onset of palpitations warrants a 24-h ECG and precipitates pulmonary edema in those with critical echocardiography to establish the degree of heart mitral stenosis. chamber enlargement and to exclude mural throm- Regurgitant valve disease The systemic vasodila- bus. If an arrhythmia is detected it should be treated tion and tachycardia that occurs in pregnancy medically or by DC cardioversion (see later). Such a reduces the regurgitant fl ow of blood allowing preg- patient should be fully anticoagulated with treatment nancy to be tolerated far better than in those with doses of LMWH. stenotic valvular lesions. Arrythmias can however Pulmonary edema should be treated with oxygen result in pulmonary oedema, and severe regurgita- and loop diuretics. Diamorphine will assist in tion with ventricular decompensation may cause reducing anxiety. A CXR usually shows a small problems. heart with an enlarged left atrium, and pulmonary congestion. Artifi cial heart valves Further deterioration despite optimal drug treatment may require surgical intervention in pregnancy. Bioprostheses are superior to mechanical (metal) Percutanous balloon valvuloplasty of mitral and prostheses in all aspects except durability. They are aortic valves has been performed in the second tri- less thrombogenic with reduced thromboembolism mester with good outcome. Mitral valvotomy is best rates and hence do not require anticoagulation. The done using transesophageal echocardiography which 10-year mortality in women with bioprosthetic valves

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is lower than with mechanical valves despite the re- Table 2.7 shows the fetal and maternal effects of operations required when bioprostheses require these regimes, which are all associated with signifi - replacement. It is the mandatory anticoagulation cant risks. In general, warfarin is safer for the mother requirement of mechanical valves that complicates but more harmful for the fetus, whereas heparin is the pregnancy. Pregnancy in a woman with a metal valve converse. Warfarin and UFH have similar fetal is associated with a maternal mortality rate of 1-4% wastage of one-third of all pregnancies. Warfarin is with death usually as a result of thrombus formation more protective against thrombosis and subsequent on the valve. The thrombotic risk varies and is out- maternal death than UFH, but is associated with sig- lined in Table 2.6. nifi cant embryopathy in surviving babies. The risks There are four regimes for anticoagulation in preg- of congenital malformations and fetal loss are nant women with mechanical heart valves: dose dependent, being signifi cantly higher if doses of greater than 5 mg are required to maintain an inter- 1. Warfarin throughout pregnancy and unfraction- national normalized ratio of greater than 2.0. Although ated heparin (UFH) or LMWH close to term. heparins do not cross the placenta, UFH is associated 2. Warfarin throughout pregnancy except weeks with a 2% incidence of maternal osteoporosis and 6-12 and near term when UFH or LMWH is used. thrombocytopenia. 3. UFH throughout pregnancy. LMWH is an attractive option as it has consider- 4. Dose adjusted LMWH throughout pregnancy ably less maternal side effects of osteoporosis (0.04%) maintaining anti-Xa level at 0.5-1.2 U/mL and thrombocytopenia than UFH, less fetal wastage and is easier to use. LMWHs have been used in pregnancy in women with mechanical heart valves, but are not licensed for use and are specifi cally not rec- Table 2.6 Thrombotic risk with mechanical ommended by the manufacturers as anticoagulants heart valves in patients with prosthetic heart valves. This was following a series of maternal deaths resulting from Risk of thrombosis valve thromboses in women who had fi xed dosing of Type of mechanical valve Single tilting disc valves LMWH in pregnancy without monitoring anti-Xa (e.g. Bjork Shiley) > levels. More recent reports where dose adjusted Ball and cage valves regimes have been used are much more encouraging. (e.g. Starr–Edwards) > Before using LMWHs, careful consideration should Bileafl et valves (e.g. be given to the individual’s thrombotic risk taking carbomedics) the factors in Table 2.6 into consideration as well as Position of mechanical valve Mitral > aortic the presence of atrial fi brillation and impaired left Number of mechanical valve 2 > 1 ventricular function. If used, an initial therapeutic Past history of embolic events Yes > no dose is advisable which is adjusted to maintain the anti-Xa level between 0.5-1.2 U/mL.

Table 2.7 Fetal and maternal risk with different anticoagulation regimes in women with metal heart valves

Fetal risks Maternal risks Anticoagulant Spontaneous Embryopathy Overall fetal Thrombosis Maternal death regime miscarriage (%) (%) lossb (%) (%) (%) Warfarina 24.7 6.4 33.6 3.9 1.8 UFH (dose- 25 0 43.8 25 6.7 adjusted) UFH (<6-12 14.7 0 16.3 9.2 4.2 weeks) + warfarina LMWHc 7.4 0 12.35 12.35 1.23

aWarfarin replaced by unfractionated heparin (UFH) at term. bSpontaneous miscarriages, stillbirths and neonatal deaths. cOnly 10% of patients were dose-adjusted according to anti-Xa levels.

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Every case should ideally be evaluated pre preg- dium or on implanted prosthetic material in the heart nancy and the woman fully counseled concerning the and can embolize to the pulmonary vasculature or risks of each treatment regimen. If she has a small Bjork systemically. Alternatively abscesses or fi stulae can Shiley valve in the mitral position with a previous occur in the heart or valve prostheses can dehisce. history of embolic events or arrhythmia and requiring The indications for antibiotic prophylaxis are given <5 mg warfarin daily then counseling should be direc- in Table 2.3 and the recommended antibiotics in Table tive towards warfarin throughout pregnancy. For a 2.8. Antibiotics should be given before a bacteremia is woman with a carbomedics valve in the aortic position expected. If antibiotic prophylaxis is not given before and no history of previous embolic or arrhythmic this event, antibiotics may help a late clearance if events requiring >5 mg of warfarin then LMWH given intravenously within 2-3 h. throughout pregnancy with careful monitoring would seem a reasonable option. Often the decision is not so When to give endocarditis prophylaxis straightforward and the woman may be unwilling to Prophylaxis against bacterial endocarditis should be contemplate any risk of warfarin embryopathy espe- given when any obstetric procedure is performed in cially if she has had a previously affected fetus. the presence of infection. The vagina contains com- mensals some of which can cause systemic infection Delivery and endocarditis in the presence of ruptured mem- If warfarin is used, it should be stopped about 10 branes. Screening for vaginal infection is not routinely days pre-delivery to allow for clearance of the drug performed, hence prophylaxis should be given to from the fetal circulation. Unfractionated heparin or women who have ruptured their membranes, at the LMWH treatment dose can be used until delivery. onset of labor, or before Cesarean section. Insertion of In labor or during induction, heparin should be cervical cerclage and urinary catheterization should stopped, but recommenced after delivery. Conversion also be covered. Procedures not requiring prophylaxis back to warfarin should be delayed for at least 3 include choriovillous sampling, amniocentesis, days postpartum to minimize the risk of obstetric vaginal examination, transvaginal ultrasound scan- hemorrhage. ning and insertion of regional analgesia. The effects of unfractionated heparin can be reversed with protamine sulfate. This also partially AORTIC DISSECTION reverses the effects of the longer acting LMWHs. War- farin is reversed with fresh frozen plasma and vitamin Rupture of the thoracic aorta and its branches has K. Such agents may be required if bleeding occurs or resulted in 19% of cardiac deaths in the UK 1991–2002. if urgent delivery is necessary in the fully anticoagu- Risk factors are Marfan syndrome with known lated patient. It is best to avoid vitamin K if possible aortic root dilatation (see above) and hypertension. as anticoagulation with warfarin postpartum then More recently bicuspid aortic valves have been becomes very diffi cult. implicated. In the event of a valve thrombus occurring in pregnancy, thrombolytic treatment should be used. The Table 2.8 Bacterial endocarditis prophylaxis regimens risks of this treatment causing embolism, bleeding or placental abruption are lower than the risks associ- Penicillin ½-1 h before ated with cardiothoracic surgery. Group allergy procedure 6 h later Antibiotic prophylaxis is mandatory to cover delivery in all women with artifi cial heart valves. High risk No Amoxycillin 2 g Amoxycillin 1 g i.v. + p.o. Gentamicin ENDOCARDITIS PROPHYLAXIS 1.5 mg/kg i.v. Yes Vancomycin 1 g – Infective endocarditis is not common in pregnancy, i.v. over 1-2 hr but can have fatal consequences for both mother and + Gentamicin fetus. The risk lies with any procedure causing bacte- 1.5 mg/kg i.v. remia and hence can occur antenatally as well as in Moderate No Amoxycillin Amoxycillin 1 g labor. Indeed most maternal deaths from bacterial risk 2 g i.v. p.o. endocarditis in the Confi dential Enquiries have not Yes Vancomycin 1 g – occurred in association with delivery. A propagation i.v. over 1-2 h of bacteria occurs on a heart valve, mural endocar-

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In pregnancy half of all reported aortic dissections Echocardiography should be performed monthly, and are in women with Marfan syndrome. Most dissec- delivery considered if the aortic root progressively tions will be Type A, which involve the ascending dilates. aorta with 88% of these occurring antenatally and A patient having an aortic dissection will have 22% being fatal. Only 20% are Type B involving only sudden onset tearing chest pain radiating to the the descending aorta which is not associated with back associated with dyspnoea. Signs include new previous aortic root enlargement or aneurysm. onset aortic regurgitation murmur and as the dissec- The risk of Type A aortic dissection occurring in tion advances, MI, CVA and hypotension. A dissec- pregnant patients with Marfan syndrome increases tion of the descending aorta may have few symptoms. with: Diagnosis is made with echocardiography, the transoesophageal route being far more sensitive, Aortic root dilatation >4 cm. • or CT. • Progressive aortic root dilatation in pregnancy. • Gestational age (most common in the third trimester). Delivery and treatment of aortic dissection Maternal age. • In those with aortic root dilatation or aneurysm, it is Family history of dissection. • imperative to prevent peaks of hypertension which However women with Marfan have a 1% risk of may result in aortic dissection. The safest mode dissection during pregnancy, even in the presence of delivery in such patients is by elective Cesarean of a normal sized aorta. Even women with no pre- section under regional blockade. Aortic repair should existing cardiac disease can dissect, thought to be due be performed postnatally as the risk of dissection to the increased cardiovascular stress in the aortic remains. wall and the hormonal changes, which affect collagen If there is a Type A dissection, immediate surgery tissue. should ensue. In general after 28-30 weeks gestation a Cesarean section under GA should be followed by Pathology cardiac surgery which will usually involve replace- Pregnancy causes alterations in the arterial wall with ment of the aortic root, aortic valve and reimplanta- fragmentation in the reticulin fi bers, and reduction in tion of the coronary arteries. Where the gestation is acid mucopolysaccharides and elastic fi bers. When earlier than 28 weeks, aortic repair with the fetus occurring in a woman with an inherited or acquired in utero is recommended if there is no distal defect in the arterial wall, dissection may result. In aortic involvement. Cardiopulmonary bypass will be Marfan syndrome there is a mutation within the required. A high-fl ow, high-pressure normothermic fi brillin gene on chromosome 15q21 which often perfusion and a perfusion index of 3.0 is considered affects the cardiovascular system and predisposes to to be the safest for the fetus. Hypothermia can cause aortic root dilatation. a fetal bradycardia resulting in hypoxic ischemic encephalopathy or even fetal death. Preconception counseling If there is associated distal involvement of the aorta in a Type A dissection, the fetus will need to be deliv- Women with Marfan syndrome or BAVD where the > ered as hypothermia is necessary for the open distal aortic root diameter is 4.5 cm should be offered pre- repair. It has been suggested that selective antegrade pregnancy aortic root replacement. The use of a com- cerebral perfusion for maternal brain protection and posite graft (i.e. an aortic root replacement with an moderate hypothermia (28 °C) can be used in this aortic valve replacement) will require anticoagulation circumstance at gestations less than 28 weeks with the with warfarin which can be changed to heparin in fetus left in utero. However, as this technique requires pregnancy (see artifi cial valves). Advice is less clear- stopping cardiopulmonary bypass whilst the distal cut for those with aortic roots of 4-4.5 cm. aorta is repaired, the fetus will not be perfused and Antenatal management hence this method is not recommended. In those with a Type B dissection, conservative Where there is aortic root dilatation > 4 cm or a pro- medical treatment should be used in the absence of gression of aortic root enlargement, beta-blockers rupture or hypotension. Delivery of the fetus should should be commenced. There is a small risk of intra- be considered as the fetal mortality is high. If there uterine growth restriction which is far outweighed are any complications with a Type B dissection, by the benefi ts. Hypertension must be aggressively immediate surgical intervention should proceed with controlled as otherwise this can lead to intimal tears. delivery of the fetus and aortic repair.

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ISCHEMIC HEART DISEASE While evidence is scarce, it appears that women who have had ACS prior to conception should ideally While acute coronary syndrome (ACS) is rare in delay pregnancy for a year after their event. These pregnancy, as women delay childbirth until their late women should preferably be revascularized prior to 30s and 40s, coronary artery problems and myocar- conception or managed very aggressively if they dial infarction (MI) are becoming more common present in pregnancy. Whether revascularized or pregnancy. Recent data from a retrospective study in medically managed, all women should ideally the USA identifi ed a threefold increase in the inci- undergo stress testing prior to pregnancy to assess dence of MI during pregnancy from 1 in 73 400 preg- their residual ischemic burden so they may be best nancies in 1990 to 1 in 24 600 in 2000. advised about the safety of pregnancy. Coronary Atherosclerosis is the predominant pathogenesis artery bypass surgery (CABG) in pregnancy, has no outside pregnancy, whereas in pregnancy coronary increase in maternal risk compared to non-pregnant artery dissection and embolus in the absence of ath- women, however is associated with a high fetal eroma are more frequent. In the last Confi dential mortality. Enquiry into maternal mortality, 18% of cardiac Delivery is often infl uenced both by the maternal deaths were from MI with 63% of these secondary to state as well as coexisting conditions such as spontaneous coronary dissection rather than plaque diabetes and pre-eclampsia. If there is no subsequent rupture. There is still on-going debate about the angina, vaginal delivery is recommended. Agents role of pregnancy-associated plasma protein A that increase blood pressure such as beta-agonists, (PAPP-A) in ACS, which is a potential proatheroscle- and ergot derivatives are best avoided or used in rotic metalloproteinase. small doses. Diagnosis outside pregnancy relies on a combination of history, ECG changes and elevation of cardiac ARRHYTHMIAS enzymes. ECG changes may require careful review as there is an incidence of up to 50% of abnormalities of The management of arrhythmias in pregnancy pro- unknown signifi cance in women undergoing vides a complex dilemma for the physician. Many Cesarean section. Troponin I (TnT) and Troponin T cardiologists do not have extensive experience in (TnT) are thought not to be increased above the upper treating these women and the knowledge that therapy limit of normal both peri- and postpartum in healthy may have an adverse effect on the fetus is intimidat- pregnant women and TnI is not affected by anesthesia ing. Diagnosing arrhythmias with Holter monitoring or Cesarean section. It does however increase in pre- can often be fruitless but treating arrhythmias blind eclampsia, pulmonary embolism, atrial fi brillation means exposing the fetus to potentially unnecessary and myocarditis. drugs. Once diagnosed, arrhythmia treatment While some drugs used in ACS are known to be requires a balance between maternal symptom control safe in pregnancy (low dose aspirin, nitrates, heparin, while avoiding or reducing any fetal complications beta-blockers and opiates) there are few data for the from anti-arrhythmic medication. While there have use of clopidogrel. Animal data appear promising, been no documented maternal deaths from primary however experience is limited to isolated case reports. arrhythmias in the last UK Confi dential Enquiry into Statins and ACE inhibitors are contraindicated maternal mortality, 9% of deaths were defi ned as because of teratogenic side effects. There are no pub- sudden adult death syndrome, which raises the lished data on either the safety or effi cacy of GIIb/IIIa possibility of death from a primary arrhythmia. In inhibitors, such as abciximab (antiplatelet agents used women with heart disease arrhythmia is one of the in the management of ACS). fi ve independent predictors of having a cardiac event Cases of MI during pregnancy have been described during the pregnancy and should therefore be treated in a variety of patients however, all appear to be asso- seriously. ciated with a high maternal and fetal mortality. Coro- nary angiography should not be withheld in pregnant Incidence of arrhythmia during pregnancy patients. Percutaneous coronary intervention may provide a better alternative to thrombolysis in these The incidence of new onset and pre-existing arrhyth- situations as it is associated with less bleeding risk mias are increased in pregnancy. As cardiac arrhyth- and also allows management of spontaneous dissec- mias can be identifi ed on Holter recordings in up to tions with stent implantation. However, stent implan- 60% of normal people under 40, it is not surprising tation may be associated with an increased risk of that the antenatal clinic sees its fair share of palpita- coronary dissection in a vulnerable vessel. tions. The increase in circulating hormones and

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cardiac physiological changes, may explain why some may still be diffi cult. An accurate symptom diary is women will present for the fi rst time in pregnancy. necessary which can be related to any abnormality on The incidence of serious arrhythmias remains low in the Holter. pregnancy despite the 25% increase in heart rate Asymptomatic arrhythmias should not be treated (HR). unless felt to be life threatening. There is no signifi cant increase in arrhythmias in Less frequent episodes or those which have evaded laboring women apart from isolated atrial premature detection are best documented using a patient acti- beats (APBs) which can occur in up to 90% of vated event recorder. These come in a number of women. models: a continuous Holter recording; a solid state recorder placed on the chest when the patient is having Cause of arrhythmias an attack; or a wristwatch with a recording electrode. These devices record approximately 30 s of ECG which The main causes of arrhythmias are similar in preg- can either be stored or transmitted down a household nant and non-pregnant women. Theories explaining telephone line to a central recording analyzer. They the increase in arrhythmia frequency in pregnancy have the advantage of recording a sequential number include: heightened awareness; increased plasma cat- of events as well as the ability to make remote diag- echolamine concentrations and adrenergic receptor nosis away from the hospital. sensitivity; atrial stretch and increased end-diastolic Finally, implantable loop recorders are increasingly volumes due to intravascular volume expansion; and being used to make diagnoses particularly in patients hormonal and emotional changes. Patients with with unexplained syncope. There is no experience of known underlying structural heart disease have a these devices in pregnancy, however there is no higher incidence of arrhythmias and many patients theoretical reason why they would not be able to may already have a diagnosis prior to conception. be used. Increased ectopy is benign and generally well tolerated but may trigger a more signifi cant arrhythmia in a susceptible individual. Types of tachyarrhythmia Once an arrhythmia has been captured then it is Symptoms important to correctly interpret the ECG. Palpitations, breathlessness, chest pain or pre-syncope may occur with arrhythmias. In the third trimester, Broad complex tachycardias patients may become more symptomatic with activity and thus even minor arrhythmias may present with A broad complex tachycardia is likely to be either these symptoms. An accurate history of the onset and ventricular tachycardia (VT) or a supraventricular offset of arrhythmias as well as the frequency, dura- tachycardia (SVT) (Fig. 2.1) with aberrant conduction. tion and character of the attacks aids the diagnosis of an arrhythmia and helps distinguish it from the physiological symptoms of advancing pregnancy. VT in the structurally abnormal heart Cardiomyopathy Diagnosis Those with cardiomyopathy, arrhythmias are the commonest cause of death outside pregnancy. ECG • Those with an ejection fraction under 35% post 24- or 48-h Holter monitor • myocardial infarction are candidates for automatic patient activated event recorder • implantable cardio-defi brillator (AICD) implantation. implantable loop recorders • The data in the non-ischemic cardiomyopathies are In a symptomatic patient with palpitations, an less robust. arrhythmia must be distinguished from physiological Hypertrophic cardiomyopathy (HCM) Non- awareness of the heart beat. An ECG is essential, sustained ventricular tachycardia (NSVT) is found although the paroxysmal, short-lived nature of most in approximately 25% of adult patients with HCM palpitations means they may have subsided by the although sustained monomorphic VT occurs in time the patient reaches an ECG machine. If an ECG less than 1% of patients Studies suggest that VT is obtained, the normal changes due to pregnancy is the single best indicator of risk of sudden should be remembered (see earlier). If not a 24-h or death in patients with hypertrophic obstructive 48-h Holter ECG may be necessary, although capture cardiomyopathy.

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Broad complex Narrow complex tachycardia* tachycardia = SVT

SVT with aberrant Re-entrant Rapid atrial VT conduction tachycardia activity

Stucturally Stuctural AVRT AVNRT Atrial Atrial Atrial normal heart = heart disease e.g. WPW tachycardia flutter fibrillation (idiopathic VT)

ECG characteristics of VT vs SVT Regular rhythm Broad complex (> 0.12 ms usually > 0.14 ms) Complexes of uniform appearance Capture of fusion beats or independent P waves present

*Always treat broad complex tachycardia as VT unless aberrancy confirmed Figure 2.1 Pathological arrhythmias.

Arrhythmogenic right ventricular cardiomyopathy Idiopathic VT Arrhythmogenic right ventricular cardiomyopathy The incidence of VT in women of childbearing age is (ARVD) is a disease characterized by progressive low unless they have signifi cant underlying heart fi brofatty replacement of right ventricular myocar- disease. VT in a young woman with a structurally dium, initially with regional and later global involve- normal heart, is more likely to be an idiopathic VT, ment of the right ventricle. It presents in adolescents which is associated with a good prognosis and low or young adults with a mean age of presentation in likelihood of degradation to ventricular fi brillation their mid-30s with a male predominance of up to 80%. (VF). Right ventricular outfl ow tract (RVOT) tachycar- The disease can be familial with an autosomal domi- dia, as identifi ed by left bundle branch block (LBBB), nant inheritance and incomplete penetrance. Presen- inferior axis and palpitations, is more common in tation is usually with arrhythmias, mainly ventricular women and states of hormone fl ux are the most and sudden death is common, particularly in the common trigger. It is important to take a careful young. It can be diagnosed in its earlier stages using family history of collapse or sudden cardiac death and MRI and later by echocardiography. Those women to review the 12 lead ECG when in sinus rhythm to diagnosed because of presentation with ventricular confi rm the patient does not have a condition associ- arrhythmias often have implantable defi brillators ated with prolonged QT interval. already inserted at the time of pregnancy Long QT syndromes In one study of 111 pregnan- Supraventricular tachycardia cies, women with long QT had no increase in risk of cardiac events in pregnancy, but they did have Premature atrial beats can be found in 50% of preg- a signifi cant risk in the postpartum period. There nant women but are generally well tolerated. In is concern that the increase in heart rate after deli- patients with documented SVT, sustained arrhyth- very coupled with the stress of caring for an infant mias are infrequent (2 to 3 per 1000 pregnancies), but may increase the risk of torsade. It is therefore imper- patients with paroxysmal SVT have exacerbation in ative that women should continue their treatment 20% of pregnancies. New onset supraventricular (usually beta-blockers) throughout the pregnancy tachycardias are also increased during pregnancy. and puerperium. Whilst SVTs are narrow complex because ventricular

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activation is via the Hiss–Purkinje system, it is managed with anti-arrhythmic drugs alone and cer- important to identify the differences between them tainly for the duration of the pregnancy. They are and not treat them all as ‘SVTs’. They can be broadly often long procedures and involve a signifi cant divided into two types, those that use an additional amount of radiation exposure. As such, both from connection between the atria and ventricles that set the logistics of a pregnant women lying fl at for up a re-entrant circuit, and those that result from many hours and the X-ray dose to the fetus even if rapid, abnormal atrial activity (Fig. 2.1). screened, the experience of EPS studies in pregnancy There are two re-entrant tachycardias: those that is limited. have an accessory pathway outside the node atrioven- There are however case reports of women tricular re-entrant tachycardia (AVRT), and those that who were refractory to medical therapy and were have the additional pathway within the AV node, experiencing recurrent hemodynamically signifi cant atrioventricular nodal re-entrant tachycardia (AVNRT). arrhythmias, who underwent successful pathway Both these arrhythmias are common with AVNRT ablation with limited fl uoroscopy. being more common in women. The duration and frequency of attacks differs between patients and, in Acute management of cardiac arrhythmias some, attacks are precipitated by exercise. The rate is Cardiac arrest usually between 130 and 250 beats per minute and is infl uenced by the sympathetic nervous system. As the Cardiac arrests are rare but if they occur it is impor- circulating impulse re-enters the atria after ventricu- tant to be aware of the differences in management of lar activation, there will be no normal p waves, though pregnant women compared to other patients. In order each QRS complex may be followed by an inverted p to optimize maternal outcome, resuscitation should wave (retrograde p). If the tachycardia is fast, this may proceed following established guidelines from the not be detectable on the surface ECG. resuscitation council. An obstetrician and pediatri- The atrial arrhythmias are divided into atrial cian should be involved from an early stage. In addi- tachycardia, fl utter and fi brillation. The mechanism is tion to the standard causes of cardiac arrest, amniotic confi ned to the atria and the AV node merely trans- fl uid embolism, pulmonary embolism, peripartum mits the impulses. Atrial fi brillation is the most easily cardiomyopathy and acute coronary or aortic dissec- diagnosed arrhythmia because of its irregular fea- tion are important causes in pregnant or recently tures, however this irregularity may be diffi cult to see delivered women. Cardiac resuscitation is more diffi - with rapid rates. The typical ‘sawtooth’ fl utter waves cult in a pregnant woman because of: are not always seen in fl utter especially at rates over aortocaval compression; 100 however a regular ECG at a rate of 150 should alert • enlarged breasts; the clinician to think about atrial fl utter with 2 : 1 con- • splinting of the diaphragm. duction. The difference between atrial fl utter and • tachycardia is that in the latter, the atrial rate is slower In the supine position the enlarged uterus can therefore the ‘sawtooth’ pattern is not seen. It maybe reduce venous return by aortocaval compression. It is therefore be diffi cult to distinguish atrial tachycardia imperative to relieve this using sand-bags or a ‘Cardiff from the re-entrant tachycardias. wedge’ under the right side of the patient, manual The diagnosis of an SVT is often helped by ade- displacement of the uterus to the left or raising of the nosine, which can be safely given in pregnancy. One woman’s right hip. Chest compression may be more of the problems of using this drug is that, blocking diffi cult because of the enlarged breasts and splinting the AV node, may encourage conduction down of the diaphragm. As gastric emptying is delayed in an accessory pathway and thus accelerate an arrhyth- pregnancy, early intubation is recommended to mia. As such, experienced personnel should give it prevent aspiration. After fi ve minutes of resuscitation, in a monitored area with equipment available for the uterus should be emptied by Cesarean section. resuscitation. There are a number of reports where this has been associated with successful resuscitation of the Electrophysiological studies in pregnancy mother.

While electrophysiological studies (EPS) are impor- DC Cardioversion tant in making accurate diagnoses of arrhythmias as well as providing the mapping for the curative radio- DC cardioversion is safe in all stages of pregnancy. frequency ablation, they are often not required as an The amniotic ﬂ uid buffers and protects the fetus, emergency. The vast majority of arrhythmias can be hence the amount of current reaching the fetus is

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small, and is associated with only a small risk of success with carotid sinus massage, whilst others inducing fetal arrhythmias. There have been reports favour the Valsalva maneuver. The re-entrant tachy- of the need for emergency CS because of fetal arrhyth- cardias using the node (AVNRT) are more likely to be mia particularly in women who are compromised; successfully terminated than those that involve an hence the fetus should be carefully monitored before, accessory pathway. An ECG should be used to monitor and throughout the procedure. One case report con- the effect of therapies as even when unsuccessful, cluded that DC cardioversion had led to sustained valuable diagnostic information can be gained for the uterine contraction and fetal distress necessitating electrophysiologist. urgent CS, but this is rare. In the latter stages of preg- If unsuccessful, termination with IV adenosine nancy, some anesthetists prefer to carry out the pro- should be attempted. Adenosine is a naturally occur- cedure using full general anesthetic and intubation in ring purine nucleotide that transiently depresses view of the more diffi cult airway and increased risk sinus node activity and slows atrioventricular (AV) of gastric aspiration. Women should be nursed in the conduction. It has an effi cacy of nearly 100% for ter- wedged position as for a cardiac arrest, otherwise the minating SVTs when given as a rapid bolus injection procedure is the same as for non-pregnant women. through a large bore cannula or central line. As the half-life of this drug is less than 10 seconds, it is rapidly metabolized by the maternal metabolism and Sustained ventricular tachycardia has no appreciable effect on the fetus. Adenosine has been shown to be safe and effective in pregnancy. Women with sustained VT who are compromised Most women respond to doses between 6 and 12 mg. with hypotension and circulatory collapse should be Verapamil is an effective second line treatment for treated immediately with cardioversion. An obstetri- the treatment of SVTs and can be used in doses up to cian should be involved and the fetus should be moni- 10 mg without effecting fetal heart rate. It should be tored. VT with hemodynamic stability can be safely given in 5 mg doses and repeated after 5 min if the fi rst treated with anti-arrhythmics. The most appropriate bolus is unsuccessful. Fetal distress has been associ- area to nurse the woman is often in the coronary care ated with verapamil induced maternal hypotension. unit (CCU) or intensive care unit (ITU), which are Beta-blockers are the drugs of choice in women familiar with the use of the drugs, and where appro- with Wolff–Parkinson-White syndrome (WPW), as priate monitoring and surveillance systems are in AV no da l blo c k i ng drugs may accelerate conduction place. Lignocaine is the drug of choice because it is through the accessory pathway and cause a deteriora- both effective and has been extensively used in preg- tion in maternal condition. nancy because of its local anesthetic properties. It is As with all arrhythmias, those associated with known to cross the placenta and result in fetal concen- hemodynamic compromise should be treated with trations around half that of the mother but no fetal DC cardioversion. adverse effects have been reported. Oral beta-blockers have been successfully used in many pregnancies particularly in women with mitral stenosis or aortic Atrial fi brillation and fl utter dilatation. Sotalol and procainamide have also been These arrhythmias are uncommon in young women. reported to be safe in pregnancy. Disopyramide If seen in pregnancy they are usually associated with should be avoided as it has been reported to stimulate congenital or valvular heart disease as well as meta- uterine contractions. As the effi cacy of intravenous bolic disturbances such as thyrotoxicosis or electro- drugs in terminating arrhythmias is 50% or less, alter- lyte disturbance. Though they may be well tolerated native methods have been explored. Reports are in conditions other than severe mitral stenosis, it is available of successful arrhythmia termination with advantageous to terminate the arrhythmia to avoid anti-tachycardia pacing following the use of a fl oata- the need for anticoagulation, particularly as preg- tion wire thus avoiding the radiation. nancy is a pro-thrombotic state. Quinidine was thought to be safe in pregnancy, but now it is rarely Re-entrant supraventricular tachycardias used outside pregnancy due to the risk of torsade de pointes. Procai namide is a safe alternative. Beta- Vagal maneuvers are easily and quickly administered blockers, verapamil and digoxin can all be used to and should be attempted fi rst while drugs or anesthe- control ventricular rate. Mexiletine, sotalol and tists are being sought. Their success ranges widely amiodarone (in the acute management) have also from 20 to 90% and some studies report a greater been used in small numbers of cases with success.

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Chronic management quinidine, sotalol and verapamil (Table 2.9). The majority of drugs available only have class C evidence Drug treatment in pregnancy for use in pregnancy. For most women beta-blockers The decision to treat a woman for chronic arrhy- are fi rst-line treatment for prophylaxis of SVT and VT thmias depends upon the frequency, duration and in pregnancy unless they enter pregnancy already on tolerability of the arrhythmia. It is a balance between alternative effective therapy such as fl ecainide. Amio- the benefi t of arrhythmia reduction or termination darone has the potential to cause thyroid dysfunction and the maternal and fetal side effects of any drug in the fetus and is usually therefore avoided. therapy. The smallest recommended dose should be Pregnancy and automatic implantable used initially and be accompanied by regular moni- cardio-defi brillators toring of maternal and fetal clinical condition. Various drugs have been used to terminate fetal arrhythmias While the world experience is still low, with the which provide useful data, although reports are increasing use of these devices, more reports of preg- predominantly case reports or small case series. nancies in women with automatic implantable cardio- Drugs used include digoxin, adenosine, amiodarone, defi brillators (AICDs) are to be expected. Successful fl ecainide, procainamide, propranolol, propafenone, pregnancies are reported, but women with frequent

Table 2.9 Anti-arrythmic drugs

Drugs Safety profi le Listed complications Breastfeeding Adenosine Safe to use in pregnancy with no Pregnant women may respond to lower doses Safe as short detectable effect on fetal due to a reduction in adenosine deaminase halfl ife cardiac rhythm Atropine Unknown but has been used for Insuffi cient data Unknown resuscitation Amiodarone Only for short-term use in If prolonged use; fetal hypo- and Avoid emergencies hyperthyroidism, goitre, IUGR, prematurity Beta-blockers Avoid atenolol in fi rst trimester IUGR, bradycardia, apnoea, hypoglycemia Safe because of concern over hyperbilirubinemia IUGR Digoxin Good safety profi le Miscarriage and fetal death in toxicity Safe Diltiazem Too little experience to comment Skeletal abnormalities, IUGR, fetal death Unknown Disopyramide Too little data to recommend Premature uterine contractions Unknown regular use Flecainide Limited literature for treatment Insuffi cient data but no reported Unknown of maternal arrhythmias signifi cant complications. however maternal ingestion Concerns over its pro-arrhythmic used to treat fetal SVT potential in fetus have limited its use in past. Lignocaine Good Fetal distress may occur in fetal toxicity Safe Quinidine Good safety profi le in pregnancy Rarely; mild uterine contractions, prem Safe however not used because of labor, neonatal TP, fetal VIIIn damage concern over safety profi le in non-pregnant women Procainamide Possibly as safe as quinidine Chronic use may be associated with lupus Safe short term in pregnancy like syndrome, GI disturbance, hypotension, agranulocytosis Propafenone Unknown Insuffi cinet data Unknown Sotalol Safe Transient fetal bradycardia Safe Verapamil Safe (fi rst choice class IV drug) Rapid injection may cause reduced maternal Safe BP and fetal distress

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arrhythmias require intensive management by a mul- cardia may, in the second trimester feel dizzy tidisciplinary team and often prolonged admission. and their blood pressure falls, however treatment One study reported a series of 44 women who under- is rarely required. Congenital heart block (CHB) went a pregnancy with an AICD implant in situ. They is rare (prevalence 1: 20 000) and the majority of reported no increases in either device or therapy com- these present before childbearing age. It does not plications and no increases in the number of shocks usually pose a problem during the pregnancy. Tem- the women received compared to pre-conception. In porary pacing is recommended during the delivery addition to standard AICD management, after each as the Valsalva associated with vaginal delivery administered shock, monitoring of the baby with a increases the chance of worsening bradycardia cardiotocograph to ensure satisfactory fetal well- and syncope as well as allowing for an adequate being may be considered. heart rate response for the increased cardiovascular Some groups have also reported the insertion of stress. the AICD in women already pregnant using echocar- Spinal anesthesia for CS can be associated with diography to guide the positioning of the leads a high incidence of all grades of bradycardia (up to and avoiding radiation exposure to the fetus. AICD 13%). Rarely, symptomatic bradycardia has been implantation may represent a safe alternative to attributed to aortocaval compression by the gravid medical therapy for ventricular tachycardia. uterus which responds to changing the maternal position. Bradyarrhythmias In the rare case of a pregnant woman requiring a pacemaker transesophageal guided lead placement Pathological bradycardia in pregnant women is should be considered which avoids the standard X-ray rare. Some women who have physiological brady- screening techniques used.

Obstetric anesthetic management of the mother with cardiac disease R. Collis

ANESTHETIC ANTENATAL ASSESSMENT Mothers with cardiac disease can be divided into AND CLASSIFICATION OF MOTHERS WITH three groups. The assessment and allocation of CARDIAC DISEASE mothers into these groups is very important because it will determine where the mother should be looked Allocating risk associated with pregnancy and deliv- after both during her pregnancy and delivery, and ery for mothers with cardiac disease is based on the how often key members of a multidisciplinary team combination of the functional class of the New York should see her. Heart Association (NYHA) see Table 2.1 and the accurate assessment of the underlying lesion. Group one The NYHA classiﬁ cation is based purely on patient function. A careful evaluation should include record- These mothers (Box 2.1) should have a normal preg- ing activities such as walking up stairs and ability to nancy. Operative delivery (elective or emergency carry out day-to-day activities such as shopping and Cesarean or instrumental vaginal delivery) should be housework. Formal assessment by exercise testing based purely on obstetric indications. may occasionally be helpful in some women (e.g. isch- These mothers should still have an early assess- emic heart disease). ment and many should have one echocardiogram

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Box 2.1 Group 1 Box 2.2 Group 2

Mothers with well-controlled and stable ischemic Deteriorating NYHA: Any cardiac lesion heart disease Continuing episodes of symptomatic ischemia Good biventricular function Moderately impaired left ventricular function No history of heart failure or pulmonary oedema EF <40% No history of major dysrhythmias Treated heart failure or pulmonary edema Congenital heart disease which has been surgically Episodes of symptomatic dysrhythmias completely corrected Palliative or partial correction of congenital heart Complete closure of patent ductus arteriosis disease Complete closure of atrial or ventricular septal Partial correction of tetralogy of Fallot defect without residual pulmonary without cyanosis hypertension Mustard’s or Senning’s procedure for Repaired coarctation of aorta transposition of the great vessels Small atrial or ventricular defects without a major Cardiomyopathy with mild to moderate ventricular shunt impairment Minor and asymptomatic pulmonary, aortic and Congenital; e.g. hypertrophic cardiomyopathy mitral stenosis Acquired; e.g. peripartum cardiomyopathy or Minor and asymptomatic mitral or aortic secondary to viral infection or multisystem incompetence disease Moderate pulmonary, aortic and mitral stenosis

during their pregnancy to confi rm the patient’s history, unless otherwise well documented. Early and rapid availability of cardiology services is therefore obstetric anesthetist, and they are best looked after in required. a hospital that can offer 24-hour specialist care in case The obstetric anesthetist should have the opportu- of sudden cardiac problems and obstetric emergen- nity to see the mother at least once during her preg- cies. Detailed anesthetic plans should be made from nancy at the beginning of the third trimester and the early part of the third trimester with desirable careful plans should be documented in the notes. The analgesia, levels of monitoring and the appropriate basis for seeing all mothers with cardiac disease antegrade of the attending anesthetist recorded. natally however asymptomatic is so that analgesia In many situations a routine low dose epidural for and anesthesia can be given without delay once in labour analgesia is a safe and appropriate choice, with labor, especially in an emergency. Ideally there should pulse oximetry and non-invasive blood pressure for be 24-h anesthetic and obstetric cover on the delivery monitoring. If a mother needs an emergency caesar- suite, but anesthetic intervention either anesthesia or ean section, the different physiological demands analgesia can usually be considered routine with the resulting from an extensive and dense regional block, normal provisos of pregnancy. a general anesthetic or blood loss more commonly associated with emergency Cesarean delivery, often Group two require a greater level of experience and monitoring than can routinely be provided in many smaller hos- There is an intermediate group of mothers with pitals. The major demands on this level of service cardiac disease (Box 2.2) that can present with deterio- provision are problems that arise outside offi ce rating parameters during pregnancy or delivery, but hours, even if an elective Cesarean section / delivery usually tolerate the physiological demands of preg- is planned. nancy without major problems. These mothers can usually tolerate labor without diffi culty (with the pos- Group three sible exceptions of asymptomatic Marfan syndrome and aortic stenosis associated with a dilated aorta > These mothers have a high risk of deterioration during 4 cm or any dilatation in pregnancy), but the anes- pregnancy (Box 2.3). The mother may present in the thetic care may need to be modifi ed. fi rst or the early part of the second trimester with These mothers should be seen from the early second heart failure, where a termination of pregnancy may trimester by a multidisciplinary team, including an be necessary or may need delivery, usually by Cesar-

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Box 2.3 Group 3 they would prefer not to have an epidural need not have one.

Pulmonary hypertension Blood pressure and cardiac output control Primary during anesthesia Eisenmenger’s syndrome (reverse shunt with cyanosis and pulmonary hypertension To maintain blood pressure during anesthesia and associated with congenital heart disease) prevent detrimental maternal problems (such as Chronic veno-occlusive disease associated reduced coronary ﬁ lling) and fetal distress, the anes- with anti-phospholipid syndrome and other thetist must control preload, afterload and heart rate. connective tissue diseases. Blood pressure (BP) is a function of cardiac output Cyanotic congenital heart disease not associated (CO) and systemic vascular resistance (SVR) and with pulmonary hypertension cardiac output is a function of heart rate (HR) and Palliative shunts from vena cava to pulmonary stroke volume (SV). This is summarized in the equa- artery tion: BP = (HR × SV) × SVR. Severely impaired ventricular function EF < 30% Regional and general anesthesia can affect all of Severe mitral or aortic stenosis especially if these parameters and it is the attention to the details associated with pulmonary edema, angina, of parameter control, rather than the absolute method dysrrythmias and collapse of anesthesia, that will provide safe analgesia and anesthesia for the mother with cardiac disease.

ean section, early in the third trimester when the baby Preload is viable. Aortocaval compression A multidisciplinary team of an obstetrician, obstet- The majority of mothers will have a degree of aorto- ric anesthetist and a physician with training in preg- caval compression at term. For many mothers it will nancy, must assess these mothers early in pregnancy be asymptomatic, until they are given an anesthetic, at around 20-24 weeks gestation. A pulmonary where it can be a major contributing factor to signiﬁ - physician may need to be included if the mother cant hypotension in up to 80% of elective Cesarean has pulmonary hypertension. Flexible and ongoing sections under spinal anesthesia. assessment will be required throughout pregnancy For the mother with cardiac disease with either as plans may rapidly change. The woman will need to poor ventricular function or a poorly compliant ven- be seen every two to four weeks in the mid-trimester tricle (especially in association with stenotic valvular of pregnancy and weekly from 30 weeks gestation. lesions), the ability to maintain an adequate stroke She will require monitoring (which may include inva- volume will be heavily dependent on good venous sive monitoring) in a high dependency area or inten- return (preload) to the right side of the heart. Minor sive care setting at the time of delivery and all plans degrees of aortocaval compression causing even a must be possible on any day and at any time. small fall in venous return can cause serious cardiac decompensation either in relation to a fall in systemic ANESTHETIC INTERVENTIONS vascular resistance associated with regional anesthesia or a further decline in ventricular contractility Cardiac output increases during pregnancy and again associated with the commonly used general anes- during labor. Part of the increase in cardiac output in thetic drugs. Mothers with cardiac disease should be labor is caused by autotransfusion during uterine con- nursed in the full lateral position to minimize aorto- tractions and part by the physiological stress response caval compression, especially in relation to establish- to pain. Regional analgesia (epidural or combined ing all regional anesthetic blocks. She should be placed spinal epidural) is the only form of pain-relief that can on her back with visible left uterine displacement for reliably obtund the pain response and is frequently the shortest possible time, should it be necessary, e.g. offered to mothers with cardiac disease. for delivery by Cesarean section, and hypotensive epi- Mothers who fall into group one and many from sodes treated with an increase in table tilt. group two will have tolerated pregnancy without dif- ﬁ culty and from the cardiovascular point of view will Hemorrhage tolerate delivery well. These mothers can be offered Hemorrhage will severely effect preload and may lead regional analgesia safely, but those that feel to early, rapid decompensation. This can be a problem

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when there is no anesthesia and early aggressive fl uid the vasopressor of choice will be the drug that main- management needs to be instituted. If hemorrhage is tains or changes maternal heart rate to within the associated with anesthesia, a fall in blood pressure range tolerated best by that mother. and coronary fi lling can be even more alarming. Ephedrine has traditionally been the vasopressor of choice in the obstetric population, with a mild ino- Monitoring preload topic and chronotropic effect. It is a useful drug in 3- Early use of central venous pressure (CVP) monitor- 6 mg boluses if the mother’s heart rate is below 80 ing can be very helpful to assess preload and should beat/min or a mild tachycardia is desirable. be considered in all mothers who have poor ventricu- Phenylephrine has traditionally been avoided in lar function and stenotic valvular lesions. An absolute obstetrics because it was feared that blood fl ow to the fi lling pressure is very much less important than fetus may be affected by its pure alpha agonist, vaso- gradual changes or sudden falls in CVP readings. A constrictor action. Recent studies have demonstrated sudden drop in CVP reading, which is usually rapidly that in the normal fetus, pH at birth may be improved followed by a drop in blood pressure, is often associ- by phenylephrine compared to ephedrine. This has ated with aortocaval compression and re-positioning led to a reassurance that phenylephrine can be used the mother is urgently required. safely for the mother with cardiac disease. It can be given either as an infusion at 10-20 µg/min or boluses Fluid therapy of 12-25 µg as required. It usually causes a refl ex Gradual changes in CVP readings over the course of slowing of the maternal heart rate to 60-70 beat/min labor can indicate under fi lling due to dehydration or and blood pressure is well maintained. over fi lling associated with over enthusiastic intravenous fl uid therapy. Both are detrimental, especially Cardiac contractility for the mother with poor ventricular function. An Regional anesthesia does not have an effect on cardiac under fi lled mother will decompensate rapidly at contractility and cardiac output is well maintained as delivery, should there be any hemorrhage. A mother long as HR and preload are maintained. Regional who has been given too much fl uid may suddenly anesthesia is particularly appropriate where cardiac develop pulmonary oedema at delivery, because of function is poor and is the anesthetic of choice in car- the additional burden of uterine autotransfusion. diomyopathy and ischemic heart disease. In normovolemia, a CVP reading is unnecessary General anesthesia may be poorly tolerated in the but intravenous fl uids should be given to judiciously mother with poor ventricular function as all general maintain a good urine output with a mother who is anesthetic drugs have a negatively inotropic action. If clinically warm and well perfused. In the face of hem- general anesthesia is required, then extreme care must orrhage, aggressive and early maintenance of hemo- be taken to maintain an appropriate heart rate using globin concentration and intravascular volume must vasopressors and vagolytic drugs as required. Inotro- be instituted. pic drugs may also be needed.

Cardiac factors Afterload Heart rate Both regional and general anesthetic techniques are A normal HR is essential for maintaining cardiac associated with a fall in afterload. This facilitates the output and blood pressure. In normal pregnancy, the forward fl ow of blood from the heart and blood pres- mother’s increase in cardiac output is largely achieved sure tends to fall. by an increase in HR. For the mother with cardiac As cardiac contractility is not affected by regional disease it is important to maintain the HR she toler- techniques, the fall in afterload can be benefi cial in ates best. some conditions. For ischemic problems, cardiac Tachycardia is especially poorly tolerated if the work is reduced and the risk of cardiac failure mother has ischemic heart disease, stenotic valvular improved. Regional techniques are also ideal for disease or hypertrophic cardiomyopathy. Bradycardia mothers with regurgitant valvular lesions, with is poorly tolerated in heart failure, a poorly compliant improved forward fl ow and a reduction in ventricular ventricle or regurgitant valvular disease. dilatation and ventricular work. A fall in afterload is particularly detrimental for Vasopressors the mother with aortic stenosis and a right to left If anesthesia is associated with a drop in blood pres- cyanotic shunt. In aortic stenosis a fall in afterload can sure, then having excluded aortocaval compression, be associated with a dramatic fall in blood pressure

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leading to poor coronary fi lling, acute ischemia and block is required to avoid problems of inadequate dysrhythmias. anesthesia during the surgery. In cyanotic shunts a fall in afterload is associated A combined spinal epidural technique can also be with an increase in right to left shunt resulting in an useful. A 5 mg intrathecal dose of bupivacaine can increase in cyanosis. Phenylephrine is the agent of usefully provide sacral anesthesia with little in the choice, as its pure alpha affect will minimize these way of hemodynamic instability and the epidural changes. component can then be used in small incremental The argument in these conditions is that general top-ups, until the desired block is achieved. Sacral anesthesia is preferable to regional anesthesia, as it anesthesia is more assured with this technique may be associated with a smaller fall in afterload. and a smaller dose of epidural bupivacaine will be There are however many good descriptions in the lit- required. erature of regional anesthesia being safely used in these conditions. It is the understanding of the patho- Uterotonics physiology of the condition and its management with Oxytocin tight, early control of cardiovascular parameters that is very much more important than the actual tech- Oxytocin is the drug most commonly used to enhance nique used. uterine contractility after delivery and reduce the risk of postpartum hemorrhage. As stated above, the risks ANESTHETIC TECHNIQUES of hemorrhage are signifi cant to the mother with cardiac disease. It is therefore important she is given General anesthesia oxytocin but the usual method of giving a bolus of 5-10 units at delivery should be avoided. For the mother with severe cardiac disease, a modifi ed Women with right heart problems and pulmo- general anesthetic technique with a small intravenous nary hypertension may tolerate the autotransfusion induction dose of thiopentone or etomidate and intra- from natural uterine contraction poorly. Additional venous opioids; fentanyl, alfentanil or remifentanil is uterine contraction associated with oxytocic drug appropriate. The mother is vulnerable to gastric regur- use may make the situation worse. Gentle manual gitation and aspiration and suxamethonium should rubbing of the uterus followed by a slow infusion still be given. The baby may have signifi cant opioid (40 u over 4-6 h) to maintain uterine contractility is induced respiratory depression due to this technique preferable. and the attending pediatrician must be made aware. Oxytocin also causes a profound fall in afterload and a refl ex tachycardia with a signifi cant increase in Regional techniques cardiac output. These physiological parameters are Labor frequently detrimental to the mother with signifi cant cardiac disease and bolus doses should be avoided if For mothers with signifi cant disease all regional tech- possible. A slow infusion will avoid these problems niques should be titrated slowly against analgesic and should be given as above. requirements. A 0.1% bupivacaine solution with fentanyl or sufentanil given in 5 ml boluses is well toler- Ergometrine ated. If analgesia is madequate combined spinal epidural technique can be considered but intrathecal Ergometrine, usually given with oxytocin, can local anesthetics should be avoided and intrathecal counter the vasodilation effect of oxytocin alone, fentanyl 25 µg or sufentanil 10 µg used as a sole agent. but the effects are unpredictable and resulting hyper- The epidural component can then be used to supple- tension can in itself be detrimental. In all but the ment the analgesia. most straightforward cases this combination should be avoided. Cesarean section Carboprost Epidural anesthesia is tolerated if given in small incremental doses. To establish a block for Cesarean section, Carboprost is a prostaglandin used to treat post 3-5 ml boluses of 0.5% bupivacaine given every 10- partum hemorrhage due to uterine atony in patients 15 min can be given. When establishing a regional unresponsive to ergometrine and oxytocin. This drug block in this way it may take 45-60 min with a total of can cause bronchospasm and hypertension, but when 25-30 mL of solution. Very careful assessment of the faced with severe hemorrhage its use should be con-

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sidered, although myocardial ischemia is a known Immer F F, Bansi A G, Immer-Bansi A S, et al 2003 Aortic side-effect. dissection in pregnancy: analysis of risk factors and outcome. Annals of Thoracic Surgery 76:309-314 Khairy P, Quyang DW, Fernandes S et al 2006 Pregnancy Physical methods outcomes in women with congenital heart disease. Circulation 113:1564-1571 The mother with signifi cant cardiac disease will not Ladner HE, Danielsen B, Gilbert WM 2005 Acute MI in tolerate major and ongoing hemorrhage. If hemor- pregnancy and the puerperium: a population based rhage occurs after vaginal delivery then early transfer study. Obstet Gynecol 105:480-484 to theatre for examination under anesthesia is impor- Lovell A T 2004 Anaesthetic implications of grown-up tant. Early initiation of invasive monitoring (blood congenital heart disease. British Journal of Anaesthesia pressure and CVP) should be considered. 93:129-139 The early use of a uterine compression or brace Ngan Kee W D, Lee A 2003 Analysis of factors associated with umbilical arterial pH and standard base excess suture such as a B-Lynch suture can lead to early after Caesarean section under spinal anaesthesia. control of hemorrhage due to placenta previa and Anaesthesia 58:125-130 uterine atony. Its use at laparotomy can avoid the con- Oran B, Lee-Parritz A, Ansell J 2004 Low molecular weight sequences of major ongoing hemorrhage and avoids heparin for the prophylaxis of thromboembolism in the continued use of the above drugs, in mothers who women with prosthetic mechanical heart valves during are intolerant of them. pregnancy. Thrombosis and Haemostasis 92:747-751 Pearson G D, Veille J C, Rahimtoola S, et al 2000 Peripartum cardiomyopathy. National Heart, Lung and Further reading Blood Institute and Offi ce of Rare Diseases (NIH). Workshop Recommendations and Review. Journal of Bachet J, Guilmet D 2002 Brain protection during surgery the American Medical Association 283:1183-1188 of the aortic arch. Journal of Cardiac Surgery 17:115-124 Reimold S C, Rutherford J D 2003 Valvular heart disease in Boyle R K 2003 Anaesthesia in parturients with heart pregnancy. New England Journal of Medicine 349:52-59 disease: a fi ve year review in an Australian tertiary Robson S C, Hunter S, Boys R J, et al 1989 Serial study of hospital. International Journal of Obstetric Anesthesia factors infl uencing changes in cardiac output during 12:173-177 human pregnancy. American Journal of Physiology 256: Chan W S, Anand S, Ginsberg J S 2000 Anticoagulation of H1060–1065 pregnant women with mechanical heart valves. Robson S K, Hunter S, Boys R, et al 1986 Changes in Archives of Internal Medicine 160:191-196 cardiac output during epidural anaesthesia for Clapp J F III, Capeless E 1997 Cardiovascular function caesarian section. Anaesthesia 44:465-479 before, during, and after the fi rst and subsequent Sadler L, McCowan L, White H, et al North R 2000 pregnancies. American Journal of Cardiology Pregnancy outcomes and cardiac complications in 80:1469-1473 women with mechanical, bioprosthetic and homograft Cotrufo M, De Feo M, De Santo L, et al 2002 Risk of valves. BJOG 107:245-253 warfarin during pregnancy with mechanical valve Siu S C, Sermer M, Colman J, et al 2001 Prospective prostheses. Obstetrics and Gynecology 99:35-40 multicenter study of pregnancy outcomes in women de Swiet M, Nelson-Piercy C 2004 Cardiac disease. In: with heart disease. Circulation 104:515-521 Confi dential enquiries into maternal and child health. Task Force on Infective Endocarditis of the European Why mothers die, 2000-2002. 6th Report of Confi dential Society of Cardiology 2004 Guidelines on prevention, Enquiries into Maternal Deaths in UK. RCOG, London diagnosis and treatment of infective endocarditis. Elkayam U, Ostrzega E, Shotan A, et al 1995 European Heart Journal 25:267-276 Cardiovascular problems in pregnant women with the Thorne S A 2004 Pregnancy in heart disease. Heart Marfan syndrome. Annals of Internal Medicine 90:450-456 123:117-122 Thorne S, Nelson-Piercy C, McGregor A et al 2006 Elkayam U, Tummala P P, Rao K, et al 2001 Maternal and Pregnancy and contraception in heart disease and fetal outcomes of subsequent pregnancies in women pulmonary arterial hypertension. Journal of Family with peripartum cardiomyopathy. New England Planning and Reproductive Health Care 32:75-81. Journal of Medicine 344:1567-1571 Weiss B M, Zemp L, Seifert B, Hess O M 1998 Outcome Felker G M, Thompson R E, Hare J M, et al 2000 of pulmonary vascular disease in pregnancy: a Underlying causes and long-term survival in patients systematic overview from 1978 through 1996. with initially unexplained cardiomyopathy. New Journal of the American College of Cardiology England Journal of Medicine 342:1077-1084 31(7):1650-1657

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