What is this patient’s most likely diagnosis and the phenomenon underlying it?
A 68-year-old male complains to his nurse practitioner that when he tests his blood pressure using a machine at his pharmacy, his heart rate is nearly always very low. At other times, he feels that his heart is racing, and it also seems to pause at times. The man has also occasionally had lightheadedness and a recent syncopal episode. What is this patient’s most likely diagnosis and the phenomenon underlying it?
