OBJECTIVES We hypothesized that orthotopic heart transplantation with bicaval and pulmonary venous anastomoses preserves atrial contractility. BACKGROUND The standard biatrial anastomotic technique of orthotopic heart transplantation causes impaired function and enlargement of the atria. Cine magnetic resonance imaging (MRI) allows assessment of atrial size and function. METHODS We studied 16 patients who had undergone bicaval (n = 8) or biatrial (n = 8) orthotopic heart transplantation without evidence of rejection and a control group of 6 healthy volunteers. For all three groups, cine MRI was performed by combining coronal and axial gated spin echo and gradient echo cine sequences. Intracardiac volumes were calculated with the Simpson rule. Atrial emptying fraction was defined as the difference between atrial diastolic and systolic volumes, divided by atrial diastolic volume, expressed in percent. All patients had right heart catheterization. RESULTS Right atrial emptying fraction was significantly higher in the bicaval (mean [+/- SD] 37 +/- 9%) than in the biatrial group (22 +/- 11%, p < 0.05) and similar to that in the control group (48 +/- 4%). Left atrial emptying fraction was significantly higher in the bicaval (30 +/- 5%) than in the biatrial group (15 +/- 4%, p < 0.05) and significantly lower in both transplant groups than in the control group (47 +/- 5%, p < 0.05). The left atrium was larger in the biatrial than in the control group (p < 0.05). Cardiac index, stroke index, heart rate and blood pressure were similar in the transplant groups. CONCLUSIONS Left and right atrial emptying fractions are significantly depressed with the biatrial technique and markedly improved with the bicaval technique of orthotopic heart transplantation. The beneficial effects of the latter technique on atrial function could improve allograft exercise performance.