Ventricular Standstill Occurring in Different Age Groups

African Journal of Emergency Medicine (2014) 4, e12–e15

African Federation for Emergency Medicine African Journal of Emergency Medicine

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CASE REPORT

‘‘Be still my beating heart’’: Ventricular standstill occurring in diﬀerent age groups

Tais-toi mon cœur battant: La pause ventriculaire dans diﬀe´rents groupes d’aˆge Richard M. Lynch *, Louise Ballesty, Rawle Maicoo Emergency Medicine, Midland Regional Hospital, Mullingar, Co. Westmeath, Ireland

Received 20 November 2013; revised 11 February 2014; accepted 15 February 2014; available online 1 August 2014

Introduction: Ventricular standstill is an uncommon yet potentially fatal arrhythmia, which requires urgent recognition and treatment. As the name suggests, the ventricles come to a standstill with an almost immediate cessation of cardiac output. If this persists for more than a few seconds the patient will lose consciousness and no pulse will be palpable. Recommended treatment includes prompt initiation of cardiopulmonary resuscitation, and if return of circulation is achieved, pacemaker insertion is usually required. Case report: Four case reports are presented which highlight the ECG features of ventricular standstill and that this arrhythmia can occur across a wide range of ages. Conclusion: Ventricular standstill can occur at any age. It can be difﬁcult to diagnose with many cases only evident on pre-hospital ECG recordings. It may present as recurring episodes of loss of consciousness yet the patient may be well in the intervening period. During episodes of ventricular standstill failure to palpate the pulse and/or over reliance on cardiac monitoring and automated ECG analysis programmes to determine the heart rate, may result in dramatic overestimation of the heart rate and may lead to delays in initiation of cardiopulmonary resuscitation and pacing if required.

Introduction: La pause ventriculaire est une arythmie peu courante, mais potentiellement mortelle, qui nećessite un diagnostic et un traitement urgent. Comme son nom l’indique, les ventricules se mettent en pause, avec un arreˆt quasi-imme´diat du de´bit cardiaque. Si cette pause persiste pendant plus de quelques secondes, le patient perdra conscience et le pouls ne sera plus palpable. Le traitement recommandećonsiste a` pratiquer rapidement une reánimation cardio-pulmonaire, et si le cœur repart, l’insertion d’un pacemaker est geńe´ralement nećessaire. Etudes de cas: Quatre e´tudes de cas sont pre´senteés, qui soulignent les caracte´ristiques a` l’ECG de la pause ventriculaire; elles re´ve` lent e´galement que cette arythmie peut survenir sur une large fourchette d’aˆge. Conclusion: La pause ventriculaire peut survenir a` tout aˆge. Elle peut eˆtre difficile a` identifier, de nombreux cas n’apparaissant qu’a` l’ECG reáliseávant l’arriveéa` l’hoˆpital. Elle peut se pre´senter sous forme d’e´pisodes de perte de conscience rećurrents, mais le patient peut e´galement se sentir bien lorsqu’elle se produit. Lors des e´pisodes de pause ventriculaire, l’absence de prise de pouls et/ou le recours excessif a` l’e´lectrocardioscope et aux programmes d’analyse automatique des ECG pour de´terminer la fre´quence cardiaque peuvent re´sulter sur une surestimation conside´rable de la fre´quence cardiaque et retarder l’initiation de la reánimation cardio- pulmonaire ainsi que la stimulation cardiaque si celle-ci s’ave` re nećessaire.

African relevance formation or blockage in the transmission of these impulses from the atria to the ventricles resulting in asystolic cardiac 2 Ventricular standstill is an uncommon, yet potentially fatal arrest. Slow ventricular escape rhythms with broad QRS com- 3 arrhythmia. plexes may also be observed. Ventricular standstill can occur at any age. As the name suggests the ventricles come to a standstill with an almost immediate cessation of cardiac output. If this persists for more than a few seconds the patient will lose con- Introduction sciousness and no pulse will be palpable. Recommended treatment includes cardiopulmonary resuscitation,4 and if return of circulation is achieved, pacemaker insertion is usually Ventricular standstill (also called ventricular asystole) is a 5 required. Typical ECG appearances of ventricular standstill potentially lethal arrhythmia if not treated promptly.1 It are the absence of any ventricular activity despite the presence occurs when there is cessation of supraventricular impulse of atrial activity, with or without ventricular escape rhythm.1,3 * Correspondence to Richard M. Lynch. [email protected] The prognosis from asystole is extremely poor with only 2– Peer review under responsibility of African Federation for Emergency Medicine. 5% of patients, in one study, who suffered an out of hospital asystolic cardiac arrest surviving to hospital discharge.6 There- fore prompt diagnosis is required and treatment commenced without delay. Production and hosting by Elsevier http://dx.doi.org/10.1016/j.afjem.2014.02.005 2211-419X ª 2014 Production and hosting by Elsevier on behalf of African Federation for Emergency Medicine. Ventricular standstill e13

We present four cases of ventricular standstill, which occurred in patients of very different ages; a young child, a young female, a middle-aged female and an elderly male. These cases highlight the fact that ventricular standstill can occur at any age.

Case reports

Case 1: A 14 month-old boy was brought to our emergency Figure 1b Automated ECG analysis recorded the heart rate at centre (EC) by his parents in the early hours of the morning. 134 bpm when in fact it was only 20 bpm. He had been unwell for a few days with vomiting and a lower respiratory tract infection. He had a background history of history of note. Following a number of presentations to her pulmonary hypertension. His condition worsened that night general practitioner and the EC, 24-h Holter monitoring was when he had a witnessed episode of unresponsiveness and performed. This revealed several brief episodes of ventricular apnoea. On arrival at the EC he was extremely ill with decom- standstill (Fig. 2). She was referred for pacemaker insertion. pensated hypotensive shock as evident by the presence of Case 3: A 50 year-old female was brought to our EC by hypotension, listlessness, cold to touch and mottling of the ambulance following six witnessed episodes of loss of con- skin. The automated ECG analysis programme recorded a sciousness. Each episode lasted only seconds and she recovered heart rate of 134 beats per minute (bpm) when in fact the cor- rapidly and completely each time without any treatment. She rect rate was only 20 bpm (Fig. 1b). This error occurred was previously well, had no relevant past medical history, because the tall broad P waves, from pulmonary hypertension, and no risk factors for cardiovascular disease. A rhythm strip were mistaken for QRS complexes (Fig. 1a). This resulted in a recorded during the last of these episodes revealed marked seven fold overestimation of the heart rate and delayed sinus bradycardia at a rate of 30 bpm followed by a 12-s period initiation of cardiopulmonary resuscitation by several minutes. of ventricular standstill (Fig. 3). No episode of ventricular At a rate of 20 bpm, chest compressions should have been per- standstill occurred in the hospital prior to pacemaker insertion. formed whereas at a rate of 134 bpm chest compressions would Case 4: An 82 year-old male presented to our EC after suf- not be indicated.2 fering two witnessed episodes of collapse with loss of con- While being treated he suffered a sudden cardiac arrest. sciousness at home. He did not report any symptoms prior Following prolonged resuscitation, in excess of 45 min, return to these episodes. These persisted for only a few seconds and of spontaneous circulation was achieved. He was subsequently he recovered quickly without the need for any medical treat- transferred to a tertiary paediatric centre where he underwent ment. These occurred following minimal exertion; walking a insertion of a permanent pacemaker and made a full recovery. few steps after standing up. On arrival of the ambulance the Case 2: A 19 year-old female self-presented to our EC with patient was alert, vital signs were normal and he had no a 3-month history of dizziness, feeling light headed and on a symptoms following these episodes. Background history of few occasions felt as if she was going to pass out, although this hypertension, which was well controlled for many years, was did not happen. She was previously well and had no family noted. He did not have any previous cardiac history and apart

Block arrow: Ventricular escape rhythm Small arrows: Tall P waves secondary to pulmonary hypertension

Figure 1a Ventricular standstill with escape rhythm at a rate of 20 bpm with broad and tall P waves. e14 R.M. Lynch et al.

Figure 2 Ventricular standstill recorded on a Holter monitor.

Figure 3 Severe sinus bradycardia progressing to ventricular standstill.

Figure 4 Ventricular standstill in an 82 year-old male.

from hypertension he did not have any risk factors for cardio- Table 1 Causes of ventricular standstill.1,8 vascular disease. 1 En route to hospital he had a further three episodes of col- Causes of ventricular standstill lapse with loss of consciousness. These lasted no more than a Myocardial ischaemia or infarction few seconds and resolved even before a pulse check could be Degeneration of the sinoatrial or atrioventricular nodes performed. He recovered instantly on assessment of respon- Medications e.g., amiodarone, beta blockers, calcium channel siveness. The cardiac rhythm recorded during one of these epi- blockers and digoxin sodes (Fig. 4) revealed sinus bradycardia and a premature Electrolyte imbalance ventricular complex after which ventricular standstill for just Acidosis Cardiogenic shock under three seconds developed before return to sinus rhythm. Precipitated by increased vagal tone No further episodes occurred after arrival to our EC.

Discussion In many patients these episodes are so short that clinical evidence of cardiac arrest, i.e., absent pulse, is not conﬁrmed These four cases highlight a number of important points when before the patient recovers. The patient may simply appear dealing with ventricular standstill. In three of the four cases, to have gone ‘‘blank’’ before recovering completely. Ventric- no evidence of ventricular standstill was observed in the hospi- ular standstill, as a result, can go undiagnosed or be mis- tal and the diagnosis was reliant entirely on pre-hospital diagnosed as another rhythm such as complete heart recordings in two patients and Holter monitoring in another block7 or another condition, such as epilepsy.8 In ventricular patient. Patients who present to the hospital following a num- standstill no evidence of ventricular activity will be seen ber of episodes of collapse with loss of consciousness should be other than perhaps a slow escape ventricular rhythm in placed on continuous cardiac monitoring and any ECG some patients where as in complete heart block, while ven- recordings performed by the paramedics should be scrutinised tricular activity is evident, it bears no relationship to atrial carefully. Despite several episodes of loss of consciousness, in activity (P waves).3,9 some cases, patients may appear well when assessed in the EC Ventricular standstill usually occurs in patients with and their ECGs may be normal. However, this does not rule structural heart disease (Table 1) but it has also been out ventricular standstill as a cause for their collapse. The reported in patients with normal heart structure.10,11 ECG should always be interpreted in the context of the Ventricular standstill should be considered amongst the patient’s history and clinical ﬁndings and not rely solely on differential diagnoses of recurrent episodes of collapse. Car- the ECG monitor. A detailed history is required to identify diac or Holter monitoring should be utilised in accordance any contributory factors that might be present. with clinical suspicion. Ventricular standstill e15

The widespread availability of cardiac and blood pressure References monitoring may result in an overreliance on their use at the expense of performing pulse checks in critically ill patients.7 1. Vassalle M. On the mechanisms underlying cardiac standstill: Failure to perform pulse checks may have resulted in delayed factors determining success or failure of escape pacemakers in the identification of ventricular standstill and delays in commenc- heart. J Am Coll Cardiol 1985;5(6):35B–42B. ing cardiopulmonary resuscitation in our 14-month old boy 2. Surawicz B, Pellegrino EE. Sudden cardiac death. New York: (Case 1). Grune and Stratton; 1964. 3. Ufberg JW, Clark JS. Bradydysrhythmias and atrioventricular conduction blocks. Emerg Med Clin North Am 2006;24:1–9. Conclusion 4. Neumar RW, Otto CW, Link MS, et al. Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Ventricular standstill can occur at any age. On arrival at the Guidelines for Cardiopulmonary Resuscitation and Emergency EC the cardiac rhythm may well have returned to normal Cardiovascular Care. Circulation 2010;122(Suppl. 3):S729–67. and the patient may be asymptomatic. During episodes of ven- 5. Toff WD, Camm AJ, Skehan JD. Single-chamber versus dual- chamber pacing for high-grade atrioventricular block. N Engl J tricular standstill failure to palpate the pulse and/or overreli- Med 2005;353(2):145–55. ance on cardiac monitoring and automated ECG analysis 6. Engdahl J, Bang A, Lindqvist J, et al. Can we define patients with programmes to determine the heart rate may result in dramatic no and those with some chance of survival when found in asystole overestimation of the heart rate and may lead to delays in out of hospital? Am J Cardiol 2000;86(6):610–4. initiation of cardiopulmonary resuscitation and pacing if 7. Leonard PA, Burns JE. Failure to recognise ventricular standstill. required. Emerg Med J 2002;19:86–7. 8. Cookson H. Paroxysmal ventricular standstill. Br Heart J Conflicts of interest 1952;14(3):350–6. 9. Petsas AA, Pinto R, Kotler MN. Sudden and unexpected ventricular standstill in acute myocardial infarction. Chest The authors declare no conflict of interest. 1973;63(3):386–90. 10. Sidhu M, Singh HP, Chopra AK. Surviving ventricular standstill for 111 seconds during Holter monitoring. Ann Noninvasive Acknowledgments Electrocardiol 2012;17(1):61–2. 11. Ergul Y, Otar G, Nisli K, et al. Permanent cardiac pacing in a We would like to thank Mr. Mathew Halligan for his assis- 2.5 month old infant with severe cyanotic breath=holding spells tance with digitising the ECG tracings. and prolonged asystole. Cardiol J 2011;18(6):704–6.