Use of exercise doppler echocardiography to evaluate cardiac drugs: Effects of propranolol and verapamil on aortic blood flow velocity and acceleration

AbstractThis study evaluated the ability of exercise Doppler echocardiography to identify hemodynamic changes due to cardiac medication. Twenty young healthy volunteers (mean age 30 years) underwent continuous wave Doppler examination from the suprasternal notch at rest, during each stage of a standard exercise protocol and immediately after exercise. On completion of the control test, each subject received either 60 to 80 mg of propranolol or 120 mg of verapamil orally, and the same exercise protocol was repeated after 90 min.During the control test, values for modal velocity, accelaration and flow velocity integral all increased significantly from baseline (p < 0.0002 for each). When exercise was repeated after propranolol administration, values for all Doppler measurements were significantly altered. Modal velocity at baseline was significantly lower after propranolol when compared with control (0.53 ± 0.11 versus 0.63 ± 0.17 m/s; p < 0.0001). Similarly, modal velocity at maximal exercise was significantly lower after propranolol (1.11 ± 0.2 versus 1.25 ± 0.21 m/s; p < 0.0001). The effect of propranolol on acceleration was even greater, with blunting of baseline (11.4 ± 2 versus 15.4 ± 5 m/s per s; p < 0.0005) and exertional (33.4 ± 10 versus 56.3 ± 15 m/s per s; p < 0.0001) acceleration. The flow velocity integral during exercise was greater after propranolol (14.1 ± 3.1 versus 10.1 ± 3.2 cm; p < 0.0005) than during the control test. Verapamil failed to influence any Doppler-measured index of aortic blood flow.It is concluded that: 1) propranolol exerts a profound hemodynamic effect as measured by Doppler echocardiography at rest and during exercise; 2) despite its negative inotropic properties, propranolol results in an increased stroke volume during exercise, apparently because of increased preload; 3) verapamil, in the dosages studied, does not alter the Doppler-measured exercise response in young healthy subjects; and 4) Doppler echocardiography is a useful technique for evaluating the hemodynamic effects of medication on aortic blood flow at rest and during exercise