Abstract
Witnessed sudden cardiac death due to paroxysmal atrioventricular (AV) block during ambulatory monitoring occurred in a 56‐year‐old female with primary conduction system disease. The control tracings showed right bundle branch block. Holter recordings obtained during the fatal event revealed paroxysmal complete AV block followed by ventricular asystole of approximately 13 seconds which, in turn, preceded the emergence of a slow idioventricular rhythm. The patient was definitely alive 5 minutes and 10 seconds following the onset of the AV block (since she activated the event marker in the recorder twice) and, possibly, 8 minutes later. Complete AV block persisted until the cessation of all cardiac activity, which took place 47 minutes following the occurrence of AV block. It is very likely that this patient could have been resuscitated in a city having a rapidly responding rescue squad.
