Myocardial ischemia due to vasospasm of small coronary arteries detected by methylergometrine maleate stress myocardial scintigraphy

Background: Recently, several case reports have implicated vasospasm of sma ll coronary arteries in vasospastic angina pectoris. Vasospasm of small cor onary arteries was also considered from angiographic findings in patients w ith atypical chest pain. In Syrian hamster, vasospasm in small coronary art eries was considered to be the cause of dilated cardiomyopathy. Hypothesis: This study was undertaken to determine whether vasospasm in sma ll coronary arteries can be induced by methylergometrine maleate stress tha llium-201 (Tl-201) myocardial scintigraphy. Methods: Twenty-five patients with chest pain, all of whom had intact coron ary arteries, were studied. After intracoronary methylergometrine maleate i njection, coronary arteriograms also looked normal in all cases. Thallium-2 01 myocardial scintigraphy was carried out immediately after intracoronary methylergometrine maleate injection in four patients with chest pain. In th e remaining 21 patients with chest pain, methylergometrine maleate was give n intravenously within up to 2 weeks before Tl-201 myocardial scintigraphy. Results: In the intracoronary injection study, one patient had chest discom fort after methylergometrine maleate injection, and ST-segment elevation wa s observed on electrocardiogram (ECG). Of the 21 patients with chest pain, 11 patients felt angina-like chest pain after intravenous injection of meth ylergometrine maleate, but their ECGs showed no ischemic changes. Stress Tl -201 myocardial scintigrams showed methylergometrine maleate-induced perfus ion defects with complete redistribution in 3 of 4 patients in the intracor onary injection study and in 12 of 21 patients in the intravenous injection study. These findings suggest that vasospasm in small coronary arteries ca used myocardial ischemia in 15 of 25 patients (60%) with chest pain. Conclusion: Vasospasm in small coronary arteries may be involved in the myo cardial ischemia of some patients with chest pain who do not show any large coronary artery vasospasm.