Left ventricular reserve of the hypertrophied heart in patients with systemic hypertension and hypertrophic cardiomyopathy--relation to age and left ventricular relative wall thickness.

To determine the effects of aging and concentric hypertrophy on the reserve of the left ventricle (LV), 36 patients with hypertension (HT), 22 with hypertrophic cardiomyopathy (HCM) and 25 age-matched normal subjects (N) were studied by isoproterenol (ISP) infusion echocardiography. The end-diastolic LV relative wall thickness (RWT), fractional shortening (FS), peak mitral flow velocity during the rapid filling phase (R) and atrial systole (A), and the A/R ratio were measured. At rest, the RWT and A/R were larger in groups HT and HCM than in group N. There were no significant differences in age, heart rate (HR), and FS among the groups. The A/R of all groups showed a good positive correlation with increasing age. The A/R of the HT group was also positively correlated with RWT. During ISP infusion, the HR, R, A, A/R and FS increased in all groups. The changes in R and FS were smaller in groups HT and HCM than in group N. The change in HR in groups N and HT, and the change in FS in all groups during ISP infusion were all inversely correlated with increasing age. The change in FS during ISP infusion was inversely correlated with RWT in the HT group, but not in HCM. Thus, it was suggested that the impairment of LV reserve in patients with HCM is not only caused by concentric hypertrophy and the aging process, but also by other myocardial factors.