- History of recurrent syncope (Electrocardiographic history suggestive of arrhythmia syncope (e.g. bifascicular block, sinus bradycardia < 40 beats per minute in absence of sinoatrial block or medications, pre-excited QRS complex, abnormal QT interval, ST segment elevation leads V1 through V3 [Brugada syndrome], negative T wave in right precordial leads and epsilon wave [arrhythmogenic right ventricular dysplasia/cardiomyopathy]))