PATHOPHYSIOLOGY OF CONGENITAL AND VALVULAR HEART DISEASES VALVULAR HEART DISEASE – CASE STUDY 1 ET is a 60-year-old woman who has been admitted from the emergency room after an episode of syncope. On the day of admission, while in church, she felt a "tingling" in her forehead. This was followed by a sudden loss of consciousness, and she awoke after about 5 minutes. At that time, her mental status was normal, and she had no focal neurologic complaints. Paramedics were called, and they brought her to the emergency room. Additional questioning discloses that about 2 months ago, she had a "gray- out" spell. She has had a known heart murmur since age 40, but she has not been evaluated further nor told she had a "heart problem." She maintains a vigorous life-style and has no history of chest pain, palpitations, or shortness of breath. Physical examination reveals a slightly obese woman in no distress. Her blood pressure is 148/92 mm Hg in both arms. Her heart rate is regular at 74 beats/min. HEENT: normal fundi; no thyromegaly, and carotids are grade 2+ bilaterally with transmitted murmurs. Chest: clear to auscultation. Cardiac: sustained but nondisplaced PMI; carotid upstroke is normal; S1 is normal; a 3/6 midpeaking systolic ejection murmur and an S4 are heard; no diastolic murmur is appreciated. Extremities: no edema, and pulses are full and symmetrical. Neurologic examination findings are normal. What is most probable valvular lesion in this patient? What symptoms and signs confirm that suspition? What is possible cause of that lesion? VALVULAR HEART DISEASE – CASE STUDY 2 A previously healthy but inactive 42-year-old man is seen in the ER after his first episode of syncope, which occurred while he was playing full-court basketball for the first time in 10 years. On questioning, he describes a 2- month history of exertional chest pain. He has not seen a physician during his adult life. Physical examination reveals the following findings. His supine blood pressure is 100/80 mm Hg without any significant orthostatic change. There is no jugular venous distention, but there are slowly rising, small-amplitude, and somewhat sustained arterial pulses. His lungs are clear. A sustained and slightly laterally displaced apex beat is noted, as well as a soft S1, and single S2, prominent S4, and a grade 3/6 harsh, late- peaking, crescendo-decrescendo systolic murmur heard best at the cardiac base and radiating to the carotids with a high-frequency component at the cardiac apex. No clubbing, cyanosis, or edema is noted. 1. What is the most likely valvular lesion in this patient? 2. What is the most likely underlying cause of that lesion in this age group? 3. What causes left ventricular concentric hypertrophy in the course of that lesion? VALVULAR HEART DISEASE – CASE STUDY 3 A 50-year-old woman who had an "innocent" murmur diagnosed in childhood presents with dyspnea on exertion, orthopnea, and paroxysmal nocturnal dyspnea of several months' duration. On questioning she describes a 1- year history of fatigue and exhaustion that has limited her daily activities. She has not seen a physician in years. On physical examination, her blood pressure is found to be 110/70 mm Hg. Her jugular venous pressure is 8 cm H2O and she exhibits 1+ pulses with normal arterial upstrokes and bibasilar rales. There is a laterally displaced apex but with a palpable S3, a soft S1 a widely split S2, a loud S3, and a grade 3/6 blowing, high-pitched, systolic murmur heard best at the apex and radiating to the axilla and left infrascapular area. There is trace edema but no clubbing or cyanosis. 1. What is the valvular lesion in this patient? 2. What are possible underlying causes of that lesion? 3. What are possible complications of that lesion? Heart murmurs • result of turbulent blood flow • functional murmur (physiologic/innocent/benign) primarily due to physiologic conditions outside the heart • structural murmurs (pathologic murmurs) – narrowing or leaking of valves – presence of abnormal passages Mechanisms of murmur formation MECHANISM EXAMPLE increased flow through a normal aortic systolic murmur in structure anemia stenosis obstruction to flow mitral stenosis and aortic turbulence murmur stenosis flow into a dilated chamber vortex aortic valve is of normal size formation when the blood flows from and the aorta is dilated a narrower to a larger chamber relative constriction membrane, which vibrates as the papillary muscle rupture fluid flows by flow of blood from a high pressure ventricular septal defects chamber to a lower pressure chamber Structural heart murmurs • categorization by timing – systolic – diastolic – continuous MITRAL STENOSIS (MS) Causes of mitral stenosis (MS) • rheumatic endocarditis (most common) • tumors • bacterial growth • calcification • thrombi • combination of MS with a congenital atrial septal defect (Lutembacher’s syndrome) Rheumatic fever • systemic disease affecting the Valvular changes: peri-arteriolar connective tissue • leaflet thickening • can occur after an untreated • commissural fusion Group A Beta hemolytic • streptococcal pharyngeal shortening and thickening of the infection tendineous cords • antibody cross-reactivity - Type II the main opening shrinks hypersensitivity reaction - molecular mimicry • B cells-derived plasma cells produce antibodies against the cell wall of Streptococcus (M protein) • The antibodies may also react against the perivascular connective tissue rheumatic fever Pathomechanism of MS stenosis increased flow resistance diminished blood flow across the valve from left atrium to left ventricle during diastole reduced cardiac output Compensatory mechanisms in MS • Peripheral oxygen extraction: arteriovenous oxygen difference (AVDO2) can increase • Diastolic filling time per unit of time can be increased by reducing the heart rate stroke volume is raised more than proportionately increased cardiac output • increase in left atrial pressure (PLA) increase of the pressure gradient between atrium and ventricle (PLA – PLV) diastolic flow rate (Qd) is raised despite the stenosis ventricular rate is the diastolic Negative effects of compensation also increased duration is (tachyarrhythmia) reduced the left atrium shortened hypertropies and pressure in LA high pressure in LA diastolic filling dilates (P mitrale in rises time the ECG) pressure increase in the pulmonary dyspnea damage of the LA atrial fibrillation veins hemoptysis varicosis of from ruptured bronchial veins lack of proper veins contraction of the formation of thrombi fibrillating atria pulmonary pulmonary edema hypertension increased risk of arterial emboli with infarction (especially of the brain) increased stress right heart on the right failure heart MS symptoms The total opening area (OA) at the mitral valve ring is normally 4–6 cm2. Main symptoms of MS • Dyspnea • Fatigue • Hemoptysis Severity of symptoms depend on OA • OA <2.5 cm2 symptoms develop on strenuous physical activity • OA < 1.5 cm2 during ordinary daily activities • OA < 1 cm2 at rest • OA < 0.3 cm2 incompatible with life Cardiac auscultation in MS • The first heart sound (I or S1) is loud and delayed (up to 90 ms, normally 60ms) • The second heart sound (II or S2) is followed by the so-called mitral opening snap (MOS), which can best be heard over the cardiac apex. Murmurs: • mid-diastolic murmur (MDM) • presystolic crescendo murmur (PSM) caused by the rapid inflow (poststenotic turbulence) during systole of atria MS pathophysiology - summary MITRAL REGURGITATION Mitral regurgitation – MR (mitral insufficiency) • the mitral valve has lost its function as a valve • during systole some of the blood in the left ventricle flows back (“regurgitates”) into the left atrium Causes • mitral valve prolapse (Barlow’s syndrome) the chordae are too long the leaflets bulge into the left atrium, where they open • rheumatic or bacterial endocarditis the leaflets and chordae shrink, thicken, and become more rigid impaired valve closure • coronary heart disease rupture of a papillary muscle / poor contraction • Marfan’s syndrome (genetic, generalized disease of the connective tissue) lengthened chordae / dilated annulus part of the stroke volume is pumped back into the LA MR pathophysiology regurgitant volume may amount to as much as 80% of the SV the regurgitant volume/ time is dependent on Effect increased volume load • Mitral opening area in systole on the left heart • Systolic pressure in the LV • Compliance (distensibility ) of the LA • Duration of systole Two versions of MR Acute MR Chronic MR • Low atrial compliance • High atrial compliance • High pressure in the LA • Pressure in the LA and in pulmonary veins is only • Increased pressure in moderately raised pulmonary veins and • High amount of blood is capillaries pumped back to LA during • Pulmonary oedema LV contration • Stroke volume in decreased fatigue • LV dilation and LV failure Auscultation of the heart • Systolic murmur • Rapid filling wave third heart sound (III or S3) • Contraction of dilated atrium high amount of blood pumped into LV fourth heart sound (IV or S4) AORTIC STENOSIS Causes of aortic stenosis (AS) • subvalvar and supravalvar stenosis • congenital stenosis malformations of the valve (age at manifestation < 15 years) • congenital bicuspid malformation of the valve (manifestation up to 65 years of age) • rheumatic–inflammatory stenosis of an originally normal tricuspid valve • degenerative changes along with calcification (manifestation in elderly Pathophysiology of AS Increased systolic