Hemodynamic effects of calcium channel and beta-receptor antagonists: evaluation by Doppler echocardiography

To evaluate the ability of Doppler echocardiography to identify hemodynamic changes due to cardiac medications, 10 volunteers underwent Doppler examination at rest and immediately following vigorous treadmill exercise. Upon completion of the control test, each subject received moderate oral doses of propranolol, verapamil, pindolol, or nifedipine, and the same exercise protocol was repeated. During four control tests, values for peak acceleration and flow velocity integral were similar for each subject at rest and exercise. Following propranolol and pindolol, resting acceleration fell by 4.5 and 2 m/sec2, respectively p less than 0.05. Resting acceleration was unchanged by verapamil and increased following nifedipine by 1.7 m/sec2 (p less than 0.0001), but neither verapamil nor nifedipine altered either Doppler parameter. Flow velocity integral was increased by nifedipine at rest and by each of the beta-blockers during exercise (p less than 0.05). We conclude that (1) rest and exercise Doppler measurements are stable and reproducible, given stable cardiovascular status; (2) pindolol produced less hemodynamic depression as measured by Doppler echocardiography at rest relative to propranolol, but showed similar potency at maximal exertion; (3) nifedipine enhanced global cardiac performance at rest, but neither calcium antagonist affected Doppler measurements during exercise; and (4) Doppler echocardiography is a useful, noninvasive technique for evaluating hemodynamic effects of medication at rest and during vigorous exercise.