A 60-year-old man with no known medical history was admitted to our emergency department following an episode of syncope. The patient was at work when he suddenly developed tunnel vision and lightheadedness followed by loss of consciousness for 10 seconds. There was no chest pain, shortness of breath, or palpitations. His blood pressure was 118/37 mm Hg, with a heart rate of 38 beats/min. He was alert and oriented. Heart sounds were normal with an irregular rate, no murmurs or gallop, and symmetric pulses. An initial electrocardiogram (ECG) was obtained (Figure 1).