The purpose of this study is to determine which pacing mode after coronary artery bypass grafting in patients with reduced left ventricular function is hemodynamically favorable.

Patients with severely reduced left ventricular function undergoing coronary artery bypass grafting (CABG) are at an increased perioperative risk and often need prolonged postoperative treatment on intensive care units. A significant portion of these patients require postoperative pacing. Right ventricular pacing has been shown to be hemodynamically deleterious whereas biventricular pacing improves cardiac output in patients with severely reduced left ventricular function and bundle branch block. The purpose of this study is to compare DDD-right ventricular, DDD-biventricular and AAI pacing in CABG patients with an ejection fraction less than 40% in a prospective randomized setting.

Inclusion Criteria:

• Elective or urgent coronary artery bypass grafting
• Preoperative ejection fraction less than 40%

Exclusion Criteria:

• Existing permanent pacemaker or ICD
• Concomitant valve surgery
• Preoperative cardiovascular instability requiring intubation or IABP use
• Chronic renal failure requiring dialysis
• Failure to provide informed consent