Noninvasive gated cardiac blood pool imaging with technetium-99m autologous erythrocytes was employed to differentiate reversible verus irreversible abnormal ventricular segmental contraction by regional wall and pump responses to sublingual nitroglycerin in 25 patients with chronic coronary heart disease. In 12 patients without ECG infarctions compared to 13 with infarctions, radioisotopic images demonstrated significantly greater percent decreases in end-systolic volumes (33.8 +/- 6.7 SEM vs 187 +/- 4.4; P less than 0.05) without differences in percent reductions in end-diastolicvolumes (13.7 +/- 3.9 vs 11.6 +/- 6.1; NS) and thereby significantly greater percent increases in ejection fractions (9.3 +/- 1.6 vs 4.1 +/- 2.0; P less than 0.05). In the 22 patients with regional dyssynergy, improvement in disordered pattern and extent of localized dyssynergy following antianginal action of nitroglycerin was related to ECG absence of prior infarction. These obsevations demonstrate the clinical accuracy of atraumatic scintigraphy in the detection of reversible localized dyssynergy due to myocardial ischemia in coronary heart disease.