Effect Of Nifedipin And Nitroglycerin On Epicardial Coronary-Arteries In Coronary-Heart Disease

The effect of nifedipine and nitroglycerin on the diameter of epicardial coronary arteries, the stenosis diameter, as well as arterial blood pressure and heart rate were recorded in 20 patients with coronary-heart disease. Nifedipine (20 mg sublingually) caused a significant fall in arterial pressure and a significant rise in heart rate. Additional administration of nitroglycerin (0.8 mg sublingually) caused a further fall in arterial pressure while heart rate remained constant. A definite relaxation (vasodilatation) of the epicardial vessels was demonstrated after nifedipine and a further increase after nitroglycerin. While nifedipine on average led to a significant increase in the diameter at the site of stenosis, response of individual stenoses was highly variable. In one patient with subtotal stenosis of the anterior interventricular branch a complete, transitory occlusion at the site of the stenosis occurred during nifedipine medication. This paradoxical reaction was not noted after nitroglycerin. Relaxation of the epicardial coronary arteries by nifedipine with suppression of phasic tone thus seems to be the major part of its anti-anginal effect. This effect is potentiated by nitroglycerin so that the combination of nitrate and calcium-antagonist appears to be therapeutically reasonable. In individual patients, however, there may be a paradoxical reaction to nifedipine.