A man in his 80s presented for his 1-month follow-up after bioprosthetic aortic valve placement for severe aortic stenosis. At presentation, he was feeling well and denied chest pain or dyspnea, and an electrocardiogram (ECG) was obtained (Figure 1). He had a history of paroxysmal atrial fibrillation, first degree atrioventricular block, and sick sinus syndrome for which a dual-chamber permanent pacemaker (PPM) had been placed a year prior. The lower rate limit of this device had been increased from 60 beats per minute (bpm) to 80 bpm in the perioperative setting of the recent valve placement procedure. Two weeks later, evaluation of his device revealed underlying atrial fibrillation with 97% ventricular pacing. The lower rate limit was decreased back to 60 bpm at that visit.