Pathogenesis and treatment of angina pectoris at rest as seen from its response to various drugs

To twenty six patients with angina at rest (including 13 patients with Prinzmetal's variant angina), propranolol 40--50 mg, dilitiazem 60--90 mg, dipyridamole 50 mg, atropine sulfate 0.6 mg and phenoxybenzamine 10--20 mg were given at 9:00 p.m. and 2:00 a.m. (except phenoxybenzamine which was given only at 9:00 p.m.) to examine the effect of these drugs on the attack. Propranolol was not only ineffective in suppressing the attack but rather tended to aggravate it in all the cases of Prinzmetal's variant angina. It was effective to some degree in 5 of 13 cases of angina at rest other than Prinzmetal's variant angina. Diltiazem suppressed the attack completely and dramatically in all the cases of angina at rest (including Prinzmetal's variant angina). Dipyridamole was ineffective in all the cases except one in suppressing the attack. Atropine sulfate and phenoxybenzamine suppressed the attack in 13 of 21 cases and in 6 of 12 cases respectively. Coronary arteriography was done before and after the intravenous administration of 10 mg of diltiazem in 8 patients and it was demonstrated that diltiazem dilates large coronary arteries in all these patients. It is concluded that diltiazem, a calcium antagonistic drug, is specifically effective in suppressing the attack of angina at rest by dilating large coronary arteries and that the autonomic nervous system plays a role in the genesis of the attack probably by constricting large coronary arteries by way of alpha adrenergic receptors.