Optimized Biventricular Pacing in Allograft Recipients

This study is designed to increase the benefit of biventricular pacing (BiVP), which is an established therapy for advanced heart failure. The investigators will test 6 left ventricular (LV) pacing sites and 16 timing sequences in the operating room just before cardiac transplant. Pacing will be implemented after patients have been anticoagulated and connected to the heart-lung machine. Pacing by previously implanted pacemakers will be suppressed. The investigators will measure cardiac output (CO) by aortic flow probe (AFP), left ventricular (LV) contractility by a combination of trans-septal pressure gradients, and simultaneous left ventricular pressure (LVP)and transesophageal echocardiography (TEE) during transient reduction of inflow of blood to the heart by vena caval occlusion. The goal is to prove that this optimization will increase the amount of blood pumped by the failing heart by 15% as compared with standard atrial (AAI) pacing. The testing protocol is 12.5 minutes in duration, and the entire protocol should be executable in 20 minutes. Care will not be altered otherwise. Results will improve management of the general population of patients with advanced heart failure while minimally increasing the risk to patients undergoing cardiac transplantation. Benefits of this study should include: improved patient selection for BiVP and a decrease in the presently recognized 30-40% incidence of BiVP nonresponders.