Anterior conduction delay: a possible cause for prominent anterior QRS forces.

Prominently anterior QRS forces often present a diagnostic dilemma. Frequently, right ventricular forces may be eliminated on clinical grounds and dorsal infarction is therefore suspected, especially in a clinical setting of coronary artery disease. In five such patients studied angiographically, the coronary disease was concentrated in the left anterior descending artery and the ventricular dysfunction confined to the anterior wall of the left ventricle. In a sixth case, the prominent anterior forces were observed intermittently together with left anterior hemiblock. These observations, in addition to serial studies following surgery, strongly suggest that the mechanism for prominent anterior QRS forces in these cases is conduction delay in an anterior division of the left bundle branch system.