We report the case of a young man who underwent orthotopic heart transplant at the De Gasperis Centre in May 1986. The patient, who was affected by Becker myopathy, was started on an immunosuppressive regimen consisting of cyclosporin and prednisone. The initial postoperative period was complicated by 2 moderate-severe rejection episodes which were treated successfully with i.v. steroids and rabbit anti-thymocyte globulin; after this period he was clinically well. On his first annual post-transplantation admission in February 1987 he was normotensive. Cardiac catheterization revealed normal hemodynamic status, completely normal coronary arteries and good left ventricular function. On re-admission in May 1989 the patient did well; he had a normal clinical status. No heart murmur was heard. Cardiac catheterization revealed abnormal right ventricular function (restrictive-constrictive physiology), normal cardiac index, apical hypokinesia of left ventricle with E.F. of 0.57. No QP/QS was detectable by oximetry. Coronary angiography showed the presence of a multiple coronary fistula. The latter arose from septal perforation of the left anterior descending artery and from the conus branch of the right coronary artery, respectively; both drained into the right ventricle. The development of these coronary fistulas was interpreted as a sequela to repeat endomyocardial biopsy. This hypothesis is supported by the fact that this kind of fistula drains uniformly into the right ventricle and generally does not arise directly from a major coronary artery.