Effects of Verapamil and Propranolol

To determine the effects of verapamil on left ventricular (LV) systolic function and diastolic filling in patients with coronary artery disease (CAD), we performed gated radionuclide angiography at rest and during exercise in 16 symptomatic patients before and during oral verapamil therapy (480 mg/day). Twelve patients were also studied during oral propranolol (160-320 mg/day). LV ejection fraction at rest was normal in 13 patients, but abnormal diastolic filling at rest, defined as peak filling rate (PFR) < 2.5 end-diastolic volumes (EDV)/sec or time to PFR > 180 msec, was present in 15. During verapamil, resting ejection fraction decreased (control 50 ± 10% [± SD], verapamil 45 ± 12%, p < 0.005), but resting diastolic filling improved: PFR increased (control 1.9 ± 0.6 EDV/sec, verapamil 2.3 ± 0.9 EDV/sec, p < 0.005) and time to PFR decreased (control 185 ± 38 msec, verapamil 161 ± 27 msec, p < 0.05). Exercise ejection fraction did not change during verapamil (control 42 i 13%, verapamil 43 ± 12%, NS), but exercise PFR increased (control 3.1 i 0.9 EDV/sec, verapamil 3.6 i 1.1 EDV/sec p < 0.05) and exercise time to PFR decreased (control 108 ± 30 msec, verapamil 91 ± 17 msec, p < 0.05). In contrast, propranolol did not alter ejection fraction, PFR, or time to PFR at rest or during exercise. Thus, LV ejection fraction is decreased by verapamil at rest but is unchanged during exercise. While LV systolic function is not improved by verapamil, LV diastolic filling is enhanced by verapamil, both at rest and during exercise. These mechanisms may account in part for the symptomatic improvement in many patients during verapamil therapy.