Exercise tests occasionally induce a QRS axis shift. Recent reports ha ve suggested that exercise-induced QRS axis shift may be related to coronary artery disease (CAD). Revievving exercise test electrocardiograms of 32 patients with severe obstructive lesions in the left anterior descending coronary artery, we examined the incidence of QRS axis shift and relation of QRS axis shifts with ischemic heart disease. QRS axis of 32 patients with CAD and 20 normal subjects without CAD who undement coronary arteriograms were measured before and after exercise testing. QRS axis shift was 60 degrees or more to the left in three patients (9.3%) with severe obstructive lesions in the left anterior descending coronary artery. These observations indicate that an exercise-induced left axis shift is an important sign suggesting severe obstructive lesions in the proximal portion of left coronary artery.
Key words: QRS axis shift, Exercise test, Coronary artery disease
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