Coronary artery to middle cardiac vein fistula following endomyocardial biopsy in a heart transplant patient.

Coronary artery fistulas draining directly into the right ventricle have been recognised as a complication of transvenous endomyocardial biopsy procedures performed in heart transplant recipients. We report a case where a fistula drained into the middle cardiac vein and outline the possible mechanism of occurrence and its prevention. The diagnostic and therapeutic aspects of these "acquired" fistulas are reviewed.