Computer-aided quantitation of the effect of nitroglycerin and isosorbide dinitrate on thallium-201 redistribution in patients with myocardial infarction

To determine whether administration of nitroglycerin (NTG) and computer-aided image analysis applied 3 hr after exercise (ex) can provide data equivalent to those available from redistribution (R) imaging 24 hr post-ex, 3 hr and 24 hr post-ex imaging with and without NTG were employed to study 15 pts with 37 coronary artery territories which were abnormal post-ex. In the 3 hr R images after NTG, 19/37 territories showed R, while only 12 were identified in the absence of NTG (p=.07); at 24 hr post-ex, 24/37 territories had R with NTG vs 13 without (p<.01). At 3 hr, defect size decrease was significantly greater after NTG than without NTG (NTG:12% reduction vs control:6%, p<.03). At 24 hr, defect size decrease was similar with each strategy. NTG administration after ex improves viable myocardium detection compared to standard R imaging without NTG.