This 65-year-old woman with an eight-year history of coronary artery disease presents to the cardiac clinic for her annual assessment. She had an aortocoronary bypass surgery five years ago, and is free of angina. Her echocardiogram shows diffuse LV hypokinesis, with an ejection fraction of 33%:

• Sinus bradycardia, 55/min
• First degree AV block
• Left atrial enlargement
• Right superior axis deviation
• Nonspecific intraventricular block