Total orthotopic heart transplantation (TOHT) requires longer ischemic time than standard orthotopic heart transplantation (SOHT) due to bicaval and pulmonary venous anastomoses, but offers normal anatomy and synchronous contractions of the atria as well as a normal ventricular filling pattern To test if TOHT improves resting hemodynamics despite prolonged ischemic time, we analyzed 60 pts with SOHT and 66 with TOHT transplanted between 12/89 and 2/93. Ischemic time was different (142±37 vs 161±36min, p=0.004). Demographics, NYHA class, LVEF, myopathy, donor demographics and inotropes were similar. Right heart catheterization data were obtained at each endomyocardial biopsy. We included data from biopsies at 2 weeks (47 vs 50 pts) and 6 months (46 vs 46 pts) posttransplant that were free from humoral or ≥IB cellular rejection. Pts with pacemaker insertion, atrial fibrillation or β-blocker therapy at the time of biopsy were excluded Cardiac output and index were higher in the TOHT group at 2 weeks (6.1±1.4 vs 5.4±1.0I/min, p=0.01; 3.3±0.7 vs 2.9±0.6I/min/m2, p=0.005) but similar at 6 months (5.9±1.2 vs 5.6±1.4I/min. p=NS; 3.0±0.6 vs 2.9±0.7I/min/m2, p=NS). Right atrial mean pressure (RAM, mmHgI was lower with TOHT vs SOHT at both time intervals (7±4 vs 9±4, p=0.02 and 5±2 vs 7±3, p=0.0006). Pulmonary arterial (PAM) and left atrial mean pressure (PCWP) (mmHg) were similar at 2 weeks (21±6 vs 23±6, p=NS; 12±5 vs 13±5, p=NS). At 6 months PAM was similar (20±7 vs 22±6, P=NS) but PCWP was lower in the TOHT group (11±5 vs 13±5, p=0.045). Pulmonary vascular resistance (PVR, Wood-Units) was similar at 2 weeks (16±0.7 vs 1.9±1.0, p=NS) and 6 months (1.6±0.7 vs 1.7±1.0, P=NS). Heart rate (bpm) was higher at 2 weeks and 6 months with TOHT than SOHT (84±10 vs 75±12, P=0.0003 and 90±12 vs 82±9, p=0.0006). Despite a longer ischemic time, total orthotopic heart transplantation does not impair postoperative cardiac function. There is an early improvement in cardiac output, a sustained higher heart rate reflecting preservation of donor sinus node function, and a lower RA pressure, perhaps due to less tricuspid regurgitation.