Evaluation of coronary hemodynamics during exercise induced vasospasm in patients with vasospastic angina by thallium-201 myocardial scintigraphy

Eight patients with vasospastic angina (VA) underwent thallium-201 myocardial scintigraphy with two injections of thallium during exercise-induced vasospasm. Coronary hemodynamics in the group of VA patients was compared with that in 10 patients with exercise angina (EA), with the purpose of evaluating the difference in the occurrence mechanism of myocardial ischemia between the groups. All of the patients in both groups had chest pain during myocardial scanning. In the VA group, seven patients had a ST elevation and one had a ST depression on ECG, in contrast to nine patients having a depressed ST in the EA group. The group of EA patients had an increase in the hemodynamic change ratio derived from myocardial counts at exercise and at rest in both the entire and ischemic areas, although the degree of increase was slight as compared with the control group. In the VA group, however, a decreased ratio was seen in the entire area in four patients and in the ischemic area in all ten patients. Hemodynamics in the EA group was independent of an increase in myocardial oxygen demand; whereas in the VA group, the coronary hemodynamics was decreased in spite of an increased myocardial oxygen demand in the ischemic area. (N.K.)