Relationship between abnormal Q waves in lead aVL and angiographic findings. A study to redefine "high lateral" infarction.

To re-evaluate the concept of "high lateral" myocardial infarction, angiographic findings were analysed in 29 patients with remote infarction and abnormal Q waves in lead I or aVL but no abnormal Q waves in other leads and no prominent R wave in lead V1. All patients except one showed asynergy in the anterior segment on right anterior oblique left ventriculogram. Asynergies in other segments were, if present, mild or small. Critical narrowing was present in the diagonal branches or in their "parent" arteries (that is, the left anterior descending artery or left main trunk) in 28 patients but in the circumflex artery in only 3 patients. Thus, the traditional concept that a "high lateral" infarction is myocardial necrosis of the basal aspect of the left ventricle, receiving its blood supply from the circumflex artery, needs correction. "High lateral infarction" corresponds to necrosis of the area between the obtuse margin and the interventricular groove ordinarily supplied by the diagonal branches of the left anterior descending artery. Such infarctions are expressed by asynergy of the anterior segment rather than the posterior segment.