Exercise-induced coronary arterial spasm: Angiographic demonstration,documentation of ischemia by myocardial scintigraphy and results of pharmacologic intervention

Exercise-induced coronary arterial spasm is an infrequently recognized phenomenon whose mechanism and management are not well established. In two patients with reproducible exercise-induced S-T segment elevation and angina pectoris thallium-201 scintigraphy showed areas of reversible anteroapical hypoperfusion, and gated radionuclide ventriculography revealed anteroapical hypokinesia with a decrease in left ventricular ejection fraction at peak exercise. During coronary arteriography, supine exercise provoked occlusive spasm of the left anterior descending coronary artery, which at rest had only minimal plaques'. Consequently, treadmill testing was performed with five different pharmacologically provoked interventions: direct vasodilatation (nitrates), alpha adrenergic blockade (phenoxybenzamine), beta adrenergic blockade (propranolol), calcium flux blockade (verapamil), and prostaglandin inhibition (indomethacin). Exercise-induced coronary arterial spasm, manifested as S-T segment elevation and angina, was prevented by nitrates, but was not eliminated by short-term oral administration of an alpha or beta blocking agent, a calcium antagonist or a prostaglandin inhibitor. Further, beta adrenergic blockade appeared to be detrimental. Thus, this study demonstrates (1) that coronary arterial spasm may be the underlying mechanism of at least some cases of exertional angina associated with transient perfusion deficits and left ventricular dysfunction, and (2) that it may be prevented by oral nitrates.