[Differentiation of the abnormal QS complex in V1-V2 leads of standard electrocardiogram by using Frank's system of leads].

Frank's orthogonal system of leads x, y z was applied for electrocardiographic differentiation of the abnormal QS complex in V1-V3 leads of the standard electrocardiogram. Absence of the physiological Q wave in z+ lead of Frank evidences always presence of focal myocardial lesion in the anterior wall and this feature was used for electrocardiographic differential diagnosis of abnormal QS complex appearing as a result of recording of intraventricular potentials against actual focal myocardial lesion. The reported study was done in 37 patients with QS complex in V1-V3 leads in standard electrocardiogram. In 28 patients absence of the Q wave was noted in the z+ lead and presence of a scar in the anterior wall in tow-dimensional echocardiography, and in to patients presence of scar was confirmed additionally in radioisotope studies, and in one case on autopsy. In 9 patients the abnormal QS complex in V1-V3 leads was caused by recording of intraventricular potentials since in the z+ lead of Frank the Q wave was always present. Echocardiographic investigation demonstrated normal contractility of the anterior wall.