Antiischemic and Hemodynamic Effects of Intravenous Isradipine, a New Calcium Antagonist, in Coronary Heart Disease: A Comparative Double-Blind Cross-Over Study with Nifedipine

In a double-blind cross-over study, 10 patients with stable angina pectoris owing to coronary heart disease were investigated in supine position during rest and bicycle exercise for the effect of 0.4 mg of intravenous (i.v.) isradipine in comparison to 2 mg i.v. nifedipine on cardiac hemodynamics and myocardial ischemia. At rest, both drugs significantly decreased total peripheral resistance (TPR) and mean arterial blood pressure (MAP), whereas heart rate (HR) increased. The pressures and resistance of the pulmonary circulation remained uninfluenced at rest. During symptom limited-exercise, both medications reduced TPR despite an unchanged MAP. Mean pulmonary artery pressure decreased significantly after both medications, whereas right atrial pressure (RAP), pulmonary capillary wedge pressure (PCWP), and pulmonary vascular resistance (PVR) decreased significantly only after nifedipine. The improvement of mean ischemic ST-segment depression averaged 44 ± 6% (mean ± SEM, p≤ 0.01) after nifedipine and 45 ± 7% (p ≤ 0.01) after isradipine. The time until angina appeared increased after isradipine by 89 ± 28% (p ≤ 0.05) and after nifedipine by 105 ± 42% (p ≤ 0.01). Significant differences between the two medications appeared only for cardiac output (CO) at rest (p ≤ 0.05), during which state the increase after isradipine was higher than after nifedipine, and for exercise HR (p ≤ 0.01), during which state only nifedipine induced a significant increase in frequency. We conclude that at the chosen dosages the hemodynamic and antiischemic effects of isradipine are similar to the effects that occur after nifedipine