ABSTRACT
Effect of diltiazem hydrochloride on cardiac performance with particular reference to the antianginal action was studied in 17 patients with ischemic heart disease, including 12 cases of effort angina, by means of clinical and mechanocardiographic evaluations. All patients were kept on the same medications from at least 2 weeks prior to diltiazem administration until the end of the study, and were prescribed no other antianginal drugs except for liberal use of sublingual nitroglycerin. Diltiazem was given 90mg a day in three divided doses for two weeks. Clinical and mechanocardiographic evaluations, including calculations of pressure rate product(PRP), triple product(TP) and tension time index(TTI), were made before and at a weekly interval after diltiazem administration. After the medication, heart rate, blood pressure and the pre-ejection period(PEP) with its ratio to the ejection time tended to decrease, and the decreases in heart rate and the PEP at the end of two weeks were significant. The PRP, TP and TTI were also significantly decreased at the end of the second week, and the decrease in the TTI was significant even a week after the medication. An antianginal effect, which appeared within few days, was excellent to good in over 90 percent of the cases. These facts suggest that diltiazem hydrochloride has no negative inotropic action and its antianginal effecti in its early stage of the drug administration is primarily due to coronary vasodilation and, as the drug is continued, is contributed to possibly by the decrease in the myocardial oxygen consumption as well.