Sy&mic and corowy h m and This study evaluated left ventricular (LV) and coronary hemodynamic effects of intravenous nitroglycerin (NW) in the presence of 8n intravenous infusion of diittazem in 15 patients with severe coronary disease. Diitiatem (250 pg/kg boius foiowed by 1.4 pg/kg/min infurion) alone decrea6ed mean oystemic blood pre6sure (mean 5%) without changing heart rate or LV end-dtastoiic pre6sure. The rate of ri6e i’n LV pre66ure declined alightiy (4%), and peripheral redrtance decre8sed (19%). Coronary sinus (CS) and great cardtac vein (GCV) fknvs were preserved. Addition of NTG (average, 68 pg/min) decreased systemic pre66ure further (7%) as LV end-di86toiic pressure declined (5 mm Hg). There pressure changes were accompanied by a 10% increase in heart rate (compared with the heart rate found with dtttiarem atone). Peripheral resirt8nce wa6 6imiIar to values after diitiatem alone. The CS and GCV flows did not decreare. The sequence of intravenous drug administratton was reversed in three other patients with combination therapy, producing similar effects, regardiess of which drug was adminiotered first. Hemodynamic effects of intravenous diitiarem alone and its combination with intravenous NTG seemed potentially favorable for patients with ischemic heart disease. (AM HEART J 1987;113:1378.) Michel Joyal, M.D., Robert L. Feldman, M.D., Karl Cremer, Pharm.D., John Pieper, Pharm.D., James A. Hill, M.D., and Carl J. Pepine, M.D., Gainesville, Fla. Because many patients with angina require multiple drugs, such as nitrates and calcium antagonists, the use of nitrates combined with a calcium antagonist is an important topic. Mechanisms of action of nitrates are complex and in certain respects contro- versial.‘” Diltiaxem, a calcium antagonist, is often used inpatientswith ischemic heart disease. In patients at rest, dihiazem reduces myocardial oxy- gen requirements by diminishing systemic pressure without a reflex increase in heart rak4.’ Animal experiment& Q suggest that diltiaxem increases col- lateral flow or improves distribution of endocardial to epicardial flow. Direct coronary actions of diltia- zem differfrom effects of nitroglycerin (NTG), dilatorof large coronary arteries than diltiazem and other calcium antagonists.lo~ l1 In contrast, diltiaxem From the Division of Cardiology, Department of Medicine, University of Florida, and the Veterans Administration Medical Center, Supported in part by a fellowship from the Canadian Cardiovascular Research Founda- tion. Received for publication Sept. 13, 1985; revision accepted Nov. 12, 1986. Reprint requests: Robert L. Feldman, M.D., Box J-277, Division of Cardiology, Department of Medicine, College of Medicine, Gainesville, FL 32610. induces significant dilation of coronary resistance vessels, whereas NTG does not.‘, 5 Finally, calcium antagonists and NTG have different effects on human atherosclerotic coronary arteriesin vitro. Phasic myogenic activity is preferentially inhibited by calcium antagonists, whereas resting coronary tone is selectively inhibited by NTG.12, l3 Informa- tion describing left ventricular (LV) and coronary hemodynamic effects of NTG in the presence of diltiaxem is not available. Accordingly, we investi- gated coronary and systemic hemodynamic actions of this combination given intravenously in patients with angina. METHODS Patients. We studied 18 men (average age 59 years, range 43 to 74 years) who had chronic stable effort angina and underwent clinically indicated cardiac catheterization (Table I). Each patient had a stress test that evoked angina and ECG abnormalities characteristic of transient myocardial ischemia. No patient had evidence of other forms of heart disease, heart failure, or recent myocardial infarction (within 3 months). None had rest angina or ECG changes suggestive of variant angina. Data from some of these patients after diltiazem alone have been reported previously. 4*5, l4 The study was approved by 1378