[Non-invasive diagnosis of the hypertrophic portion in cardiomyopathy: comparison of electrocardiographic and vectorcardiographic abnormalities with the hypertrophic portion of the left ventricle determined by two-dimensional echocardiography (author's transl)].

The electrocardiogram, vectorcardiogram and two-dimensional echocardiogram were recorded in 18 cases with hypertrophic cardiomyopathy. Cardiac catheterization and coronary angiography were carried out in 7 cases, which revealed that the coronary arteries were normal in all cases and no abnormal findings were observed except for hypertrophy of the ventricle. In the two-dimensional echocardiographic studies, the long axis, short axis, RAO, and LAO views of the left ventricle and the 4 chamber view were recorded. The short-axis views were obtained at the level of the chorda tendineae, the papillary muscles and the region between the papillary muscles and the cardiac apex. Left ventricular wall of each level was divided into 4 segments, including anterior, lateral, medial and posterior segments. Then, the degree of hypertrophy was estimated by summing up the wall thickness of each segment at three levels. The hypertrophic portion of the cardiac muscle thus obtained from two-dimensional echocardiograms was compared with the electrocardiographic and vectorcardiographic findings and the following conclusions were obtained. 1) Relationship of electrographic findings with the hypertrophic portion of the left ventricle in the short-axis view: The group with negative T waves in I and aVL showed asymmetric septal hypertrophy (ASH) but not apical hypertrophy. In the short-axis view of the left ventricle, the anterolateral segments were hypertrophic in all the cases. The group with negative T waves in II, III and aVF, on the other hand, had apical hypertrophy (APH) in a great number. In the short-axis view of the left ventricle, hypertrophy was observed from the anterior to medial segments in many cases. So, the hypertrophic portion of the left ventricle could be presumed by the electrocardiographic leads revealing negative T waves. 2) Relationship of vectorcardiographic findings with the hypertrophic portion of the left ventricle: In 2 of 4 cases with hypertrophy in the anterior segment, the half area vector of QRS loop in the horizontal plane and the maximum vector directed left ward and anteriorly. In cases with hypertrophy in the antero-lateral segment, the vector of QRS loop directed left ward and posteriorly. In 2 cases with hypertrophy in the posterior segment, vectors of QRS loop directed posteriorly. Then, the direction of the vector of QRS loop in the horizontal plane suggested the hypertrophic portion of the left ventricle.