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SUMMARY A 37-year-old man presented with an evolving inferior myocardial infarction. Coronary angiography performed within 3 hours after the onset of the pain showed spasm of the right coronary artery and the presence of intracoronary thrombi. After resolution of spasm and the disappearance of thrombi, angiography revealed nearly normal coronary arteries. An ergonovine test was positive when the patient was not taking medication and became negative when he was taking diltiazem. The course was uncomplicated, and after 9 months the patient is free of angina.WHAT CAUSES myocardial infarction (MI) in patients with angiographically normal or nearly normal coronary arteries remains unclear. Some studies have suggested a role for coronary artery spasm,' but the importance of thrombosis has been better documented, since coronary angiography is performed within the first hours of acute MI.4 I We recently studied a patient with an acute MI associated with probable coronary artery spasm, coronary thrombosis and only slight irregularities of the coronary arterial tree.Case Report A 37-year-old white man was admitted to the coronary care unit (CCU) for prolonged anginal chest pain. He had no history of hypertension, diabetes mellitus or lipid abnormalities, but had smoked 30 cigarettes daily for 20 years. He had a 1-year history of infrequent spontaneous and exertional substernal pain. At 11:30 a.m. on December 23, 1981, he experienced a severe typical anginal pain and was admitted to the CCU at 12:45 p.m. Physical examination was normal. The chest x-ray revealed a heart of normal size. Serum creatine kinase was 23 U (normal range 0-140 U/ml). Hemoglobin was 13.2 g. An ECG showed normal sinus rhythm and 0.2 mV of ST-segment elevation in leads III and VF ( fig. 1). An inferior myocardial infarction was suspected and the patient was considered for percutaneous transluminal coronary recanalization. showed only a discrete stenosis at the site of the previous obstruction and the presence of intracoronary filling defects consistent with thrombi ( fig. 3). A second left ventriculogram showed local contraction improvement, moderate diaphragmatic and posterobasal hypokinesia and a global ejection fraction of 61%. Because of the cardiac massage, intracoronary injection of streptokinase was cancelled. The patient received i.v. heparin, 360 mg, and i.v. nitroglycerin, 25 mg daily. His clinical course was uncomplicated (no pain, arrhythmia or heart failure). The maximum CK value of 1000 U/ml was reached on December 24. The ECG ( fig. 4) fig. 5). An ergonovine test was performed in the CCU, off medication, using a progressive protocol as previously described.6 Ten minutes after the 0. 2-mg injection of ergonovine maleate, the patient experienced typical anginal pain and the ECG ( fig. 4) showed 0.2 mV of ST-segment elevation in the inferior leads, which was reversed with 0.

SUMMARY Diltiazem is a calcium slow-channel blocking drug that may be effective in the treatment of chronic stable angina pectoris. To evaluate the therapeutic efficacy 3 hours after a single oral dose of 120 mg, 12 men with chronic stable angina pectoris performed a maximal exercise test on a bicycle ergometer after ingesting either placebo or diltiazem administered in a double-blind fashion. During submaximal exercise at a fixed work load, diltiazem decreased the average heart rate response from 119 ± 17 to 107 ± 14 beats/ min (p < 0.01), systolic blood pressure from 182 ± 15 to 175 ± 15 mm Hg (p < 0.05) and the rate-pressure product from 21.8 ± 4.2 to 18.8 ± 3.2 x 10-3 units (p < 0.01). The average submaximal work load at which significant ST-segment depression (0.1 mV) first appeared was increased from 355 ± 142 to 525 + 143 seconds (p < 0.01) after diltiazem. At peak exercise after diltiazem, the average depth of ST-segment depression in any one lead and the extent of myocardial ischemia observed in all 12 ECG leads were decreased (p < 0.01), even though the average work load was increased by 29% (p < 0.01). Peak heart rate, systolic blood pressure and rate-pressure product were similar with placebo and diltiazem. The plasma diltiazem concentration was 139 ± 29 ng/ml 3 hours after ingestion and was significantly (p < 0.05) related to the increased time to the onset of important ST-segment depression (r = 0.65) and to the decrease in the extent of myocardial ischemia observed in all 12 ECG leads (r = -0.61) compared with placebo. Thus, diltiazem is effective in treating chronic stable angina pectoris. It decreases myocardial oxygen requirements during upright exercise and appears to increase myocardial oxygen delivery.THE EFFECTIVENESS of diltiazem, a calcium slowchannel blocking drug, in the prevention of coronary spasm is well documented.' It decreases systemic arteriolar resistance, increases coronary artery blood flow and has a negative chronotropic effect.t fThese properties have justified its study in the treatment of exertional angina in patients with fixed coronary artery stenoses.]-1' Repeat oral-dose studies of diltiazem show an increase in the time to the onset of angina or to significant ST-segment depression during standard multistage exercise testing.7-9 Both the total daily dose and schedule appear to influence the drug's efficacy and ability to reduce indexes of myocardial oxygen demand during exercise. Hossack and Bruce7 found a greater effect using 60 mg four times daily than smaller doses and with a schedule of 30 mg four times daily vs 60 mg three times daily. Single-dose studies'0 " with 60 and 90 mg of diltiazem have not shown a significant decrease in the indexes of myocardial oxygen demand during exercise.Therefore, in the present study, we compared, after 3 hours, the effects of a single oral dose of 120 mg of diltiazem vs placebo on the time to the onset of significant ST-segment depression (0.1 mV) and to peak exercise; the indexes of myocardial oxygen consumption at a fixed submax...