Correlation of vectorcardiographic findings with patterns of left ventricular hypertrophy in hypertrophic cardiomyopathy

We compared vectorcardiographic (VCG) findings with the distribution of hypertrophy in patients with hypertrophic cardiomyopathy (HCM). Distribution of left ventricular hypertrophy was determined by both echocardiogram (UCG) and magnetic resonance imaging (MRI). According to the specific hypertrophic site evaluated by UCG and MRI, 43 patients with HCM were classified into 4 types : septal, anterior, posterolateral or apical type. In patients classified as anterior, posterolateral and apical types, the QRS loop was directed toward the hypertrophic site because of increased electromotive force in the hypertrophic site. In contrast, in patients classified as septal types, the QRS loop was directed away from the hypertrophic site. This opposite direction was probably due to altered electromotive force and/or conduction disturbance in the hypertrophic site as the disease progressed. The present study indicates that QRS loop direction suggests the location of hypertrophy. The T loop was most slender in patients with apical hypertrophy and the slenderness was associated with the relative degree of hypertrophy in the apex compared with hypertrophy in other sites.

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