[Apical hypertrophy and catecholamine]

Catecholamine is suspected to be related to the pathogenesis of hypertrophic cardiomyopathy (HCM). To investigate the contribution of catecholamine to apical hypertrophy (APH) which is a special type of HCM, 16 normal controls, 49 +/- 4 years old; 14 patients with APH, 55 +/- 6 years old; 18 patients with other types of HCM, 53 +/- 8 years old; and 12 patients with left ventricular hypertrophy due to valvular heart diseases (VHD), 49 +/- 10 years old, were studied during treadmill exercise tests, supine ergometer tests and intravenous infusions of isoproterenol (ISP) (0.02 micrograms/kg/min for 5 min). Echocardiograms and/or electrocardiograms were obtained during the procedures. During ergometer exercise, there was no significant difference in increase of heart rates among all groups. Ergometer exercise increased the level of plasma catecholamine in the group VHD, and there was a similar but less marked tendency in the APH. During the ISP infusion, "mechanical" reaction was relatively low in the APH compared to those in the other groups. The giant negative T waves in the HCM, mostly in the APH, lessened during exercise and during the ISP infusion. Among those in whom negative T wave changes of more than 0.5 mV occurred during exercise, the wall motion of the left ventricle was more active during exercise. Giant negative T waves changed diurnally and were less deeper during daytime than at night.(ABSTRACT TRUNCATED AT 250 WORDS)