An unexpected presentation of sick sinus syndrome: Isolated ventricular asystole.
Sick sinus syndrome is a disorder of sinus node function characterized by various dysrhythmias such as sinus bradycardia or pause, paroxysmal regular or irregular atrial tachycardia, tachycardiabradycardia attacks or atrial fibrillation with slow ventricular response. Ventricular asystole with preserved atrial electrical activity is a rarely seen presenting rhythm in the ED and an extremely rare cause of syncope. A 67-year-old male having a syncope attack was admitted to the emergency department. His Glasgow coma scale score was 15 on admission. He became unconscious during his observation in the emergency department, and cardiopulmonary resuscitation was initiated because he was seen to be apneic; his arterial pulse was impalpable, and ventricular asystole with preserved atrial electrical activity was seen on the monitor. He regained consciousness and normal sinus rhythm was seen on the monitor after 2min of cardiopulmonary resuscitation. Then, an alternating rhythm with short periods of bradycardia and tachycardia suggesting sick sinus syndrome was developed. A dual-chamber pacemaker was placed, and he was discharged after 2days of in patient follow-up. His symptoms have not recurred after placement of the pacemaker device. When sudden changes in vital parameters and/or consciousness develop during observation of a patient with sick sinus syndrome, although it is not a common circumstance, accompanying high degree atrioventricular block and simultaneous ventricular asystole should be considered, and cardiopulmonary resuscitation should be initiated immediately because cardiopulmonary arrest is inevitable when ventricular asystole develops even if the atrial electrical activity is maintained.