ASSESSMENT OF LEFT-VENTRICULAR MYOCARDIAL PERFUSION AND DIASTOLIC FUNCTION DURING ACETYLCHOLINE-INDUCED DIFFUSE CORONARY VASOCONSTRICTION BY DOPPLER-ECHOCARDIOGRAPHY AND TL-201 SCINTIGRAPHY

Background: We investigated whether diffuse coronary vasoconstriction induced by acetylcholine caused myocardial ischemia. Methods: We studi ed 30 patients (40 coronary arteries) with spontaneous chest pain or e quivocal studies on treadmill exercise testing and no significant coro nary stenosis or previous myocardial infarction. During the acetylchol ine provocation test, Doppler echocardiography was performed, and thal lium-201 was injected intravenously for scintigraphy. We used Doppler echocardiography to measure the ratio of early-to-late peak mitral flo w (E:A ratio). Results: When acetylcholine was injected, the coronary arteries showed three different responses. Diffuse coronary vasoconstr iction without chest pain or ischemic changes on the ECG was induced i n 18 (45%) arteries and the E:A ratio decreased from 0.83+/-0.13 to 0. 77+/-0.13 (P = 0.031). In 17 vessels (control arteries), the E:A ratio did not change significantly (from 0.88+/-0.15 to 0.88+/-0.18; P = 0. 95). In five arteries, focal spasm was induced and the E:A ratio decre ased from 0.83+/-0.18 to 0.66+/-0.13 (P = 0.043). Transient defects on thallium-201 scintigraphy were observed in the territory of eight (80 %) arteries with diffuse vasoconstriction and in one (20%) control art ery (P = 0.047). Conclusions: Diffuse coronary vasoconstriction induce d by intracoronary acetylcholine can decrease the regional myocardial blood flow (as shown by thallium-201 scintigraphy) and can cause globa l left ventricular diastolic dysfunction (as shown by the results of D oppler echocardiography).