Twenty-five hypertensives with no history of myocardial infarction and with a radiologically determined heart enlargement were examined with M-mode echocardiography and compared with a normotensive control group (n = 41). All except two of the hypertensive patients were on a beta-blocker based antihypertensive treatment regime. The relative heart volume on X-ray was significantly larger in the hypertensives, 562 ml m-2 body surface area (BSA), compared to the normotensives, 408 ml m-2 BSA (P less than 0.001). Both left ventricular diameter (LVD) in end-diastole and end-systole and left arterial (LA) diameter were significantly larger in the hypertensives (56 vs. 51 mm, P less than 0.01; 35 vs. 31 mm, P less than 0.01; 46 vs. 42 mm, P less than 0.01, respectively) as was the LV mass (296 vs. 203 g, P less than 0.001). The end-systolic wall stress (ESWS) was significantly greater in the hypertensives. Despite these findings resting left ventricular fractional shortening was the same and showed a similar correlation with ESWS (r = 0.79 and r = 0.77, respectively) in both groups. Hence, left ventricular systolic performance was not impaired in the hypertensives compared to the normotensives. These results show that an enlarged cardiac silhouette on the chest X-ray in hypertensive subjects with beta-blocker based drug therapy must be interpreted with caution and must not, a priori, be judged as a sign of an impaired systolic cardiac function.
Adrenergic beta-Antagonists Cardiomegaly