Hemodynamic effects of nifedipine given alone and in combination with atenolol in patients with impaired left ventricular function

Abstract

The acute intravenous (IV) (0.1, 0.2 and 0.4 μg/kg/min over 10 minutes each) and chronic oral (60 mg/day) administration of nifedipine was examined in 9 patients with significantly impaired left ventricular (LV) function (ejection fraction [EF] on radionuclide scannin was 0.20 to 0.40) who were already receiving β-blocker therapy (>25% reduction in peak exercise heart rate) with atenolol, 100 to 200 mg/day. The mean control LV end-diastolic pressure (EDP) at cardiac catheterization and EF for the group as a whole were 30 ± 3 mm Hg (range 20 to 42) (mean ± standard error of the mean) and 28.5 ± 2.4%, respectively. Three of the 9 patients had hemodynamic deterioration and LV failure at some. stage during the study, and their mean LVEDP and EF were 38 ± 3 mm Hg (range 33 to 42) and 22.6 ± 2.7%, respectively. In the 6 patients who tolerated the full treatment protocol, the mean LVEDP and EF were 26.5 ± 2.0 mm Hg (range 20 to 35) and 31.5 ± 2.8%, respectively. Seven patients received IV nifedipine, which had a negative inotropic action but did not precipitate cardiac decompensation. Chronic oral administration of nifedipine in combination with atenolol precipitated LV failure only in those with the lowest EF and highest LVEDP; usually LV failure was present with atenolol alone. Extensive infarction, frequently complicated by LV failure at the time, LVEDP >32 mm Hg and control resting EF <30 % were associated with LV failure. Removal of sympathetic nervous system support for the impaired ventricle by β blockade may be the decisive factor in precipitating hemodynamic deterioration in patients with severe impairment of LV function.