Ultrasonic Features of Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery

Abstract

The congenital anomaly in which the left coronary artery arises from the main pulmonary artery is a rather rare lesion but one of great physiological and clinical importance since it is diagnosable during life, and is surgically treatable. The purpose of this report was to describe echocardiographic features of two cases with this condition proven by angiography and operation. Case 1 had a dilated, tortuous right coronary artery arising from the aorta and the left coronary artery and its branches arising from the main pulmonary artery. In case 2, both the right coronary artery and left circumflex artery originated from the aorta, whereas the left anterior descending artery arised from the pulmonary artery. The right coronary artery of case 2 was dilated of very mild degree. The electrocardiogram of case 1 showed evidences of old lateral myocardial infarction, while that of case 2 was normal. The M-mode echocardiogram obtained from case 1 demonstrated an abnormal structure anterior to the aortic root, giving an arched appearance, convex toward the chest wall in maximum systole. The cross-sectional echocardiogram of the same case visualized the origin of the dilated right coronary artery. The abnormal structure on M-mode echocardiogram was judged to originate from the origin of the dilated right coronary artery, and its pattern should be explained by the relation between the motion of the proximal portion of the artery and the ultrasonic beam pathway.