Differences in apical and non-apical types of hypertrophic cardiomyopathy: a prospective analysis of clinical, echocardiographic, and cardiac magnetic resonance findings and outcome from 350 patients

This study sought to achieve an understanding of the true structural heterogeneity of hypertrophic cardiomyopathy. The diversity and clinical significance of the morphologic expression of hypertrophic cardiomyopathy have not been fully defined within this broad disease spectrum. Patterns of left ventricular hypertrophy were characterized by two-dimensional echocardiography in a large study cohort of 600 patients (7 to 79 years old, mean age 45; 393 [66%] men) consecutively studied at two referral centers. Left ventricular wall thickness was 15 to 52 mm (mean [+/- SD] 22.3 +/- 5). A multitude of patterns of asymmetric left ventricular hypertrophy were identified, with the most common showing diffuse involvement of substantial portions of both ventricular septum and free wall. Of 16 possible patterns of left ventricular hypertrophy, 12 (78%) were identified among the 600 patients. Hypertrophy most commonly involved two left ventricular segments (228 patients [38%]) or three or more segments (202 patients [34%]), but was also localized to one segment in a substantial number of patients (170 [28%]). The anterior portion of the ventricular septum was the region of the left ventricle that most frequently showed thickening (573 patients [96%]), and was also the predominant site of hypertrophy in most patients (492 patients [83%]). Patterns of wall thickening that were either concentric (i.e., symmetric) or confined to the apex were particularly uncommon (in 1% each). 1) In hypertrophic cardiomyopathy, the distribution of left ventricular hypertrophy is characteristically asymmetric and particularly heterogeneous, encompassing most possible patterns of wall thickening, from extensive and diffuse to mild and segmental, and with no single morphologic expression considered typical or classic. 2) A greater extent of left ventricular hypertrophy was associated with younger age and more marked mitral valve systolic anterior motion and outflow obstruction but showed no relation to either magnitude of symptoms or gender.

The aim of this study was to describe long-term outcome in patients with apical hypertrophic cardiomyopathy (ApHCM) followed in a tertiary referral center. Apical hypertrophic cardiomyopathy is a relatively rare form of hypertrophic cardiomyopathy (HCM), first described in Japan. Initial reports, based on a limited number of patients, emphasized the benign nature of this condition. A retrospective study of 105 patients with ApHCM diagnosed at the Toronto General Hospital from 1975 to 2000 was performed. Symptoms, clinical findings, mortality and cardiovascular morbidity were analyzed. The mean age at presentation was 41.4 +/- 14.5 years. During a mean follow-up of 13.6 +/- 8.3 years from presentation, cardiovascular mortality was 1.9% (2/105) and annual cardiovascular mortality was 0.1%. Overall survival was 95% at 15 years. Thirty-two patients (30%) had one or more major morbid events, the most frequent being atrial fibrillation (12%) and myocardial infarction (10%). Probability of survival without morbid events was 74% at 15 years. Three predictors of cardiovascular morbidity were identified: age at presentation or = II at baseline. Forty-four percent of the patients were asymptomatic at the time of last follow-up. Apical hypertrophic cardiomyopathy in North American patients is not associated with sudden cardiac death and has a benign prognosis in terms of cardiovascular mortality. Nevertheless, one third of these patients experience serious cardiovascular complications, such as myocardial infarction and arrhythmias. These data are likely to influence the counseling and management of patients with ApHCM.