Anomalous origin of the right coronary artery from the pulmonary artery

Two patients with an anomalous right coronary artery arising from the pulmonary artery are presented. The first patient was asymptomatic and had a continuous murmur. The correct diagnosis was established by cardiac catheterization and selective angiography. There was a moderate sized shunt from the dilated left anterior descending coronary artery to the right coronary artery, which arose from the main pulmonary artery. The second patient was also asymptomatic but died several days after a sudden cardiorespiratory arrest. On postmortem examination she was demonstrated to have anomalous origin of the right coronary artery from the pulmonary artery. The left coronary artery was completely occluded at the orifice by a thrombus, and microscopic examination demonstrated evidence of both acute and chronic left ventricular ischemia and infarction. The pathophysiologic alterations and potential danger to patients with this anomaly are discussed.