Most coronary artery fistulae are congenital, arising from incomplete obliteration of the primitive myocardial sinusoids and multiple fistulous tracts. Occasionally these fistulae may result from cardiac interventions such as percutaneous transluminal coronary angioplasty or endomyocardial biopsy. Involvement of the right coronary artery is marginally more common than the left, and drainage into the …