[Apical hypertrophy as a part of the morphologic spectrum of hypertrophic cardiomyopathy].

Clinical and morphological features in 10 cases of "apical hypertrophic cardiomyopathy" (apical type) were analyzed and compared with those in classic hypertrophic cardiomyopathy with asymmetric septal hypertrophy (ASH). The hypertrophic pattern of the interventricular septum (IVS) was evaluated on the two-dimensional echocardiographic (2-D) left ventricular (LV) long-axis view. Thirty-one of 70 patients with ASH were characterized by predominant hypertrophy of the basal IVS (Type I). Seventeen patients had predominant hypertrophy of the apical IVS (Type III). Diffuse IVS hypertrophy was noted in 22 patients (Type II). Electrocardiographic similarity was documented between cases with Type III and apical type; that is, a low incidence of abnormal Q waves, a high incidence of giant negative T waves, and frequent absence of Q waves. In Type I and II, abnormal Q waves were frequently observed, while giant negative T waves were rare. On the 2-D LV short-axis view at the papillary muscle level, three groups with ASH revealed similar distributions of myocardial hypertrophy characterized by extension of hypertrophy to the LV anterior free all and papillary muscles. Most cases with apical type had a similar distribution of hypertrophy, but its degree was significantly less severe than that of ASH. Comparison of diastolic LV configurations on left ventriculograms and/or the 2-D apical two-chamber views indicated the morphologic continuity among the three types with ASH and the apical type. Clinical features in cases of the apical type were obviously less severe than those of three groups with ASH, as indicated by a significantly larger proportion of asymptomatic patients (90%), absence of sudden death and rare documentation of malignant ventricular arrhythmias on 24-hours ambulatory electrocardiography. In conclusion, apical type can be categorized as a part of hypertrophic cardiomyopathy with a wide morphologic spectrum rather than the separate disease entity, and it is characterized by giant negative T waves with minimum clinical manifestations.