An active 62-year-old man with no medical problems began to experience frequent, sudden episodes of exertional near-syncope and syncope. The episodes were not associated with any prodromal symptoms. A neurologic evaluation was unrevealing. A transthoracic echocardiogram demonstrated a structurally normal heart, and the patient’s resting electrocardiogram (ECG) was normal. On advice from his primary care physician, the patient purchased an AliveCor cardiac monitor (AliveCor) to allow recording and transmission of cardiac rhythms through his smartphone.1 During an episode of near-syncope, the patient recorded runs of wide complex tachycardia lasting up to 6 seconds (Figure 1).