Right ventricular wall images of ischemic heart disease were evaluated during exercise myocardial scintigraphy using thallium-201. Among 33 subjects, ten were normal controls, 11 had left coronary artery disease (LAD group), 12 had right coronary artery disease (RCA group), all of whom received exercise myocardial scintigraphy. The submaximal or symptom-related ergometer exercise test was performed by the protocol being with 25 watt (W) loading, and then increased by 25 W every 3 min, while 3 mCi thallium-201 were injected intravenously at the maximal exercise point. Early imaging was obtained 5 min after exercise; delayed imagings, 1 and 4 hours after exercise. Early imaging and delayed imaging at 4 hours after exercise were obtained in the AP, lateral, LAO 30 degrees, LAO 45 degrees, and LAO 60 degrees projections. Only the LAO 45 degrees was obtained for delayed imaging 1 hour after exercise. To assess the radioactivity in the right ventricular wall, with regions of interest (ROI) in the upper part of the right ventricle [RV (U)] lower part of the right ventricle [RV (L)] and the most radioactive region in the left ventricle [LV (P)], we calculated the count ratio of the RV(U) or RV(L) to the LV(P) and defined it as the RV uptake ratio [RV(U)/LV(P)] or [RV(L)/LV(P)]. The results obtained were as follows: There were no significant changes in the RV uptake ratio between the early and delayed images both in the control and LAD groups, but the RV uptake ratio decreased significantly in the delayed images compared with an early image in the RCA group.(ABSTRACT TRUNCATED AT 250 WORDS)