Varying vectorcardiographic patterns in anomalous left coronary artery arising from pulmonary artery

Abstract

Five patients with LCPA (anomalous origin of the left coronary artery from the pulmonary artery) were studied. Three of them underwent ligation of the anomalous vessel (Group I), whereas 2 had undergone pericardial phenolization some years previously (Group II). In the preoperative vectorcardiograms, morphologic configuration of the QRS vector loop in the horizontal plane was found to be variable. Clockwise inscription was found to be related to a very extensive infarction of the left ventricle. Counterclockwise inscription, on the other hand, was found in a patient with a more localized area of infarction which showed quick regression after ligation of LCPA. The patient with a loop inscribed partly counterclockwise and partly clockwise appeared to fall into an intermediate position with respect to area of infarction. It is suggested that this spectrum of morphologic configuration may serve to indicate the severity of infarction and the general outlook. Time vector analysis was found to provide useful information. After ligation of LCPA in one patient, changes indicative of regression of infarction appeared: widening of the QRS loop to the left and anteriorly in the horizontal plane and leftward shift of the mean axis in the frontal plane. Evidence of intraventricular conduction defect with features suggestive of periinfarction block was seen. On the electrocardiogram the features of interest were abnormal QRS transition in the precordial leads, varying distribution of abnormal Q waves, and slurring of QRS complexes with or without widening. Vectorcardiographic analyses were found to be useful in evaluating the severity and extent of infarction and as a guide to its regression after surgery.