[The hemodynamic effects of isradipine and nifedipine in hypertension]

Hemodynamic Effects of Isradipine and Nifedipine in Hypertension Myocardial wall tension is an important determinant of the oxygen demand, the function and the degree of hypertrophy of the left ventricle. Myocardial wall tension should be influenced more favourably by a non-cardiodepressive antihypertensive than by a potentially cardiodepressive one. Therefore, we investigated the effects of an intravenous infusion of the calcium antagonists isradipine (I; 0.4 mg; 3,5-pyridinecarboxylic acid, 4-[benzofurazanyl]-1,4-dihydro-2,6-dimethyl-,methyl-ethylester+ ++ [9CI]; CAS75695-93-1) and nifedipine (N; 2.0 mg) resp., on hemodynamics and myocardial wall tension in 12 hypertensives by an intraindividual comparison. The adrenergic reflex activation induced by vasodilation was limited by pre-medication with 0.1 mg propranolol/kg body weight (i.v.) before application of I and N. Baseline blood pressure of the patients and its changes in response to both calcium antagonists were statistically comparable, as were the left ventricular end-diastolic volumes. The end-systolic volumes, however, decreased significantly on I but not on N: before I: 69 +/- 7.0 (mean +/- standard error), after I: 61 +/- 6.1 ml, 2p less than 0,001; before N: 62 +/- 6.1, after N: 64 +/- 7.0 ml, n.s. (difference to I: 2 p less than 0.05). Stroke volume increased only on I (before I: 62 +/- 4.1, after I: 69 +/- 4.1 ml, 2p less than 0.001; before N: 64 +/- 3.5, after N: 65 +/- 3.8 ml, n.s. (difference to I: 2p less than 0.05)).(ABSTRACT TRUNCATED AT 250 WORDS)