MAGNETIC-RESONANCE-IMAGING OF APICAL HYPERTROPHIC CARDIOMYOPATHY

To assess the capability of magnetic resonance imaging (MRI) to define the presence, degree, and distribution of apical hypertrophic cardiom yopathy in patients of European descent, MRI examination was prospecti vely performed in patients diagnosed with hypertrophic cardiomyopathy on two-dimensional echocardiography. Twenty-five patients with hypertr ophy located exclusively at the cardiac apex were the object of this s tudy. Spin echo and gradient echo sequences were performed to evaluate the morphology, motility, and myocardial thickness of the left ventri cle in diastole. In a short-axis gradient echo sequence from base to a pex, septal, lateral, anterior, and posterior segments at the basal an d apical levels were measured. A four-chamber view and horizontal long -axis images of the left ventricle were performed to measure the true apex. A concentric, symmetric distribution of hypertrophic myocardium was considered when the thickness was 1.5 cm or greater, with the four segments being affected to a similar degree. Asymmetric hypertrophy w as considered when the wall thickness ratio was more than 1.3. Myocard ial thicknesses at the apical level were 2.03 +/- 0.60 cm (mean +/- st andard deviation) at the true apex; the septal thickness was 1.19 +/- 0.46 cm; lateral, 1.62 +/- 0.71 cm; anterior, 1.36 +/- 0.57 cm; and po sterior, 1.28 +/- 0.53 cm. Based on the MRI findings, the distribution of apical hypertrophy was classified as symmetric (n = 2), asymmetric (n = 18), and true apex (n = 5). A spadelike configuration of the lef t ventricle was observed in only five cases. MRI demonstrates that in Western patients the morphologic spectrum of apical hypertrophy cardio myopathy is quite wide and includes myocardial hypertrophy exclusively localized at the true apex.