ECG of the Month: A 91-Year-Old Woman With Frequent PVCs

A 91-year-old woman with a past medical history of remote coronary artery bypass surgery, hypertension, and hyperlipidemia, presented for evaluation of frequent premature ventricular contractions (PVCs) in the setting of a declining left ventricular ejection fraction. She was started on amiodarone for the PVCs that are depicted on "ECG A." She then presented back to our clinic one year later with a chief complaint of fatigue. The ECG from this clinic visit is depicted as "ECG B."

Figure 1
Figure 2

ECG B is most consistent with which of the following:

Show Answer