Coronary Artery Spasm as a Cause of Acute Myocardial Ischemia in Man

¹ From the Reparto Coronarico del Laboratorio di Fisiologia, Clinica del C.N.R., and the Unità Coronarica dell'Istituto di Patologia Speciale Medica dell'Universtà di Pisa, Pisa, Italy

The pathogenesis of "spontaneous angina" was investigated in five patients with so-called variant angina. Electrocardiographic monitoring demonstrated that several ischemic episodes were asymptomatic. Right and left ventricular pressure monitoring during 26 episodes of ST-segment elevation and two of ST-segment depression demonstrated that no hemodynamic change indicative of increased myocardial demands ever preceded the episodes, suggesting that an acute reduction of blood supply was responsible for the transient ischemia. A reduction of peak dp/dt and systolic pressure and elevation of end-diastolic pressure preceded and accompanied the ST change as observed in the animal upon sudden coronary occlusion. The hemodynamic pattern and the incidence of arrhythmias was the same in the episodes with or without pain. Coronary arteriography performed during a spontaneous episode in four patients showed complete occlusion with proximal diffuse lumen reduction and no distal filling of the vessel supplying the myocardium corresponding to the ST-segment elevation relieved by nitroglycerin administration. Thus, it appears reasonable to assume that a coronary spasm may be the cause of the acute reduction of coronary blood supply responsible for the transient myocardial ischemia in these patients. Anginal pain appears to be only a possible concomitant symptom of acute myocardial ischemia.