A man in his 70s with severe symptomatic aortic stenosis underwent transcatheter aortic valve replacement (TAVR) with a self-expanding valve. His 12-lead electrocardiograms (ECGs) prior to TAVR revealed atrial fibrillation (AF) with a narrow QRS complex at a ventricular rate of 56 beats per minute (bpm). An ECG obtained 3 days post-TAVR is shown in the Figure, A. The patient was asymptomatic and hemodynamically stable.