BIS measurements will be performed on patients both in the pretransplant and post-transplant periods except when contraindicated in the pretransplant setting concerning patients with advanced heart failure. Because the use of BIS is contraindicated in the setting of permanent pacemaker and/or internal cardiac defibrillator (ICD) devices, BIS assessment cannot be performed in the pretransplant setting for patients with advanced heart failure as the majority of these patients already have these devices in place. However, at the time of cardiac transplantation, these devices will be removed from those patients with advanced heart failure and the BIS measurements will then be performed shortly after transplantation, and then serially during the post-transplant period at various time intervals for one year in order to track changes in body composition.