Two hundred forty-five patients with variant angina were followed for an average of 80.5 months (range, 36-184 months). Survival rate at 1, 3, 5, and 10 years was 98%, 97%, 97%, and 93%, respectively. Survival rate without myocardial infarction at 1, 3, 5, and 10 years was 86%, 85%, 83%, and 81%, respectively. By univariate analysis, ST

SUMMARY Thirteen patients with Prinzmetal's variant angina performed treadmill exercise tests in the early morning and in the afternoon of the same day. The attacks with ST elevation were induced repeatedly in all 13 patients in the early morning, but in only two patients in the afternoon.Propranolol did not suppress the exercise-induced attacks in all 13 patients. Diltiazem suppressed the attacks in all 13 patients and phentolamine in eight of the nine patients.Coronary arteriograms demonstrated that spasm occluding completely or almost completely the large coronary artery supplying the area of myocardium showing ST elevation appeared during the attacks and disappeared along with the attacks after nitroglycerin administration in all four patients in whom the attacks were induced by arm exercise in the catheterization laboratory.We conclude that there is circadian variation of exercise capacity in patients with Prinzmetal's variant angina caused by coronary arterial spasm induced by exercise in the early morning but not in the afternoon.

SUMMARY Vigorous hyperventilation was induced for five minutes immediately after a five-minute infusion of 100 ml of Tris-buffer (pH 10) in nine patients with Prinzmetal's variant angina. In eight of the patients, chest pain with ischemic changes in the electrocardiogram occurred during this procedure or within five minutes after it ended. Coronary arterial spasm appeared after the procedure and disappeared after the administration of nitroglycerin in all four patients in whom coronary cinearteriography was performed. This was evident both before and after the procedure and after sublingual administration of nitroglycerin (0.6 mg). The oral administration of 90 mg of diltiazem, a calcium antagonistic drug, two hours before, completely suppressed the attack induced by the procedure in all of the five patients who received this drug.We conclude that hyperventilation plus Tris-buffer infusion induces coronary arterial spasm and anginal attack in patients with Prinzmetal's variant angina and that diltiazem suppresses these reactions.IT IS INCREASINGLY EVIDENT that coronary arterial spasm plays an important role in the pathogenesis of Prinzmetal's variant form of angina.'5 However, the mechanism by which coronary arterial spasm occurs is unknown.Contraction of vascular smooth muscle depends quantitatively on the presence of calcium ions which are required for the activation of myofibrillar ATPase.6-9 Physiologically, a highly potent calcium antagonistic action is exerted by hydrogen ions which seem to compete with calcium ions for the same active sites both at the transmembrane calcium transport system and at the myofibrillar ATPase.91 Thus, vasoconstriction occurs if calcium ion concentration increases or hydrogen ion concentration decreases, whereas vasodilatation is produced by either calcium deficiency or an increased hydrogen ion concentration.9The present study examines whether coronary arterial spasm and anginal attack could be induced by hyperventilation and Tris-buffer infusion, which decrease hydrogen ion concentration, in patients with Prinzmetal's variant form of angina. Materials and Methods Nine patients with Prinzmetal's variant form of angina were studied. All the patients had recurring attacks of chest pain in association with ST segment elevation in the electrocardiogram more than five times a week at the time of the study. Their age, sex, electrocardiogram at rest and during attack, and coronary arteriograms are shown in table 1. None of the patients had received digitalis or diuretics, and all the medications were stopped at least three days before the study, except nitroglycerin, which was stopped at least two hours before the study.Blood pressure, 12-lead electrocardiogram and arterial blood for pH and gas analysis were taken while patients were supine from 9:00 a.m. to l1:00 a.m. Patients then received a five-minute infusion of Tris-buffer 100 ml (pH 10). Immediately after, vigorous hyperventilation was performed for five minutes under the constant monitoring of blood pressure and electrocardio...

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