Systolic functional response of normal older and younger adult left ventricles to beta-blockade during exercise

Summary There is controversy over the effects of beta-blockade on the left ventricular systolic response of the heart of the elderly to stress. In this study we compared the effects of acute beta-blockade in normal older and younger adult left ventricles during exercise. The study population consisted of 17 healthy elderly people, 67±3 years old, while 18 young normal subjects, 31±4 years old, served as controls. A symptom-limited exercise treadmill test was performed before and 15 minutes after intravenous administration of 0.12 mg propranolol/kg. M-mode echocardiographic studies were performed before and immediately after each test. Intravenous propranolol at rest decreased heart rate by 14±7 beats/min in the elderly and by 7.5±8 beats/min in the young (p=0.02), decreased the double product by 2500±1200 mmHg/min and 1830±970 mmHg/min (p=0.05), respectively; changed the left ventricular end-systolic dimension by +0.21±0.36 cm and +0.03±0.24 cm (p=0.09), respectively; and changed the end-diastolic dimension by +0.22±0.46 cm in the elderly and by –0.02±0.32 cm in the young (p=0.08). The change in fractional shortening was –1.22±4.17% in the elderly and –0.78±4.05% in the young (p>0.05), and the decrease in the systolic blood pressure/end-systolic dimension ratio was 5.9±7 mmHg/cm and 4.3±3.8 mmHg/cm, respectively (p>0.05). During exercise, however, propranolol had the same effects in the two groups. These results indicate that beta-blockade has the same effects on normal older and younger adult left ventricles during exercise and is well tolerated by the elderly.