[Apical hypertrophy and its genetic and acquired factors].

Although apical hypertrophy is characterized by a spade-like configuration of the left ventricle and giant negative T waves on electrocardiograms, the identity of apical hypertrophy in the disease spectrum of hypertrophic cardiomyopathy (HCM) is not fully established. The present study compared the demography, familial occurrence, and acquired factors of 43 patients who had apical hypertrophy with those of 104 patients who had asymmetric septal hypertrophy (ASH). Demographically, apical hypertrophy occurred predominantly in middle-aged males (86%). Family surveys showed that 13% of siblings of apical hypertrophy were affected, significantly less than in obstructive (31%) or non-obstructive (29%) HCM with ASH. Thirty-eight percent of siblings of ASH patients less than 35 years of age were affected, with a male/female ratio of 4/5, suggesting an autosomal dominant inheritance. The acquired factors associated with apical hypertrophy were assessed in a case-control study. Relative risk (odds ratio) of the condition was 3.46 (p less than 0.05) in those with histories of hypertension, and increased further to 8.09 (p less than 0.001) in those who were often hypertensive according to their physician's evaluations. Thus a strong association of hypertension with apical hypertrophy was suggested. However, hypertension in this condition was usually mild and labile, the blood pressure reverted to the normal range within several days of hospital admission, implying that transient hypertension during daily activity is associated with apical hypertrophy. Therefore, blood pressure response during exercise stress tests of 25 patients with apical hypertrophy was compared with that of age- and sex-matched controls. Slopes of linear regression between systolic blood pressure and heart rate and oxygen consumption during exercise, were used as indices of blood pressure response. They were significantly greater in apical hypertrophy than in the controls (1.2 +/- 0.4 vs 0.9 +/- 0.3, p less than 0.01 and 4.3 +/- 1.7 vs 2.8 +/- 0.8, p less than 0.001). This trend was observed even in patients without histories of hypertension. These findings suggested that apical hypertrophy has an inheritance pattern different from that of ASH, and has a possible association with acquired factors such as hypertension. Therefore, apical hypertrophy seemed to be a disease entity distinct from HCM with ASH, though it might be included in the disease spectrum of HCM.