[A quantitative evaluation of coronary steal phenomenon in coronary artery-pulmonary artery fistula: case report].

A 67-year-old woman was admitted to our hospital with a complaint of anterior chest pain on exertion. Auscultation disclosed a continuous murmur and exercise electrocardiography revealed positive ischemic ST change. Coronary angiography showed a large left coronary fistula and a small right coronary fistula into the main pulmonary artery. To evaluate the influence of the fistula on coronary circulation, we measured blood flow in the left anterior descending artery (LAD) and in the fistula artery using a 0.014 inch Doppler guide wire. Before surgery, blood flow in the LAD decreased during rapid atrial pacing (130 bpm) but that in the fistula remained constant. After the surgery, there was no remarkable decrease in blood flow in the LAD during rapid atrial pacing (130 bpm), and the preoperative reduction ratio was calculated as 24% compared with postoperatively. These findings suggest that coronary steal phenomenon was involved in myocardial ischemia in this patient.