Coronary flow characteristics of multiple coronary artery-left ventricular microfistulae in young monozygotic twins.

Coronary artery multiple fistulae of the left ventricular chamber are extremely rare congenital malformations. We report on 13-year-old monozygotic twin brothers who have identical abnormalities of coronary flow reserve as well as the same morphological findings of multiple coronary fistulae of the 3 major coronary arteries to the left ventricular chamber. The left circumflex coronary artery (LCX) had abundant fine communications with the left ventricular chamber and had a higher flow rate than the left anterior-descending coronary artery. The coronary flow reserve obtained from the LCX was lower than the normal value matched for the same age group. The increased shunt flow resulted in enlargement of the left ventricular chamber. This is the first report of coronary flow characteristics in children with multiple coronary fistulae.