To assess the capability of magnetic resonance imaging (MRI) to define the presence, degree, and distribution of apical hypertrophic cardiomyopathy in patients of European descent, MRI examination was prospectively performed in patients diagnosed with hypertrophic cardiomyopathy on two-dimensional echocardiography. Twenty-five patients with hypertrophy located exclusively at the cardiac apex were the object of this study. Spin echo and gradient echo sequences were performed to evaluate the morphology, motility, and myocardial thickness of the left ventricle in diastole. In a short-axis gradient echo sequences from base to apex, septal, lateral, anterior, and posterior segments at the basal and 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 was considered when the wall thickness ratio was more than 1.3. Myocardial thicknesses at the apical level were 2.03 +/- 0.60 cm (mean +/- standard 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 posterior, 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 left ventricle was observed in only five cases. MRI demonstrates that in Western patients the morphologic spectrum of apical hypertrophy cardiomyopathy is quite wide and includes myocardial hypertrophy exclusively localized at the true apex.