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Background: In patients with coronary artery disease (CAD), the characteristics of those with discordant exercise thallium 201 single photon emission computed tomography (SPECT) lung uptake (lung-to-heart [L/H] ratio) and left ventricular (LV) transient ischemic dilation (LVTID) are not well defined., Methods and Results: The population included 310 patients having exercise Tl-201 SPECT and coronary angiography. The population was subclassified into 4 subgroups: increased L/H ratio only, increased LVTID only, both, and neither. The L/H ratio was weakly correlated to LVTID (r = 0.18). The L/H ratio was correlated to the summed difference score (r = 0.26), summed rest score (r = 0.31), summed stress score (r = 0.5), and rest and stress LV volume (r = 0.5 and r = 0.54, respectively). LVTID was only correlated to the summed difference score (r = 0.32) and stress LV volume (r = 0.17). Increased LVTID only was associated with more frequent ischemia and patients with it tended to be more extensively ischemic, as compared with patients with increased L/H ratio only, but had a similar angiographic extent of CAD. These results were independent of prior myocardial infarction variable., Conclusions: As compared with patients with increased L/H ratio alone, patients with increased LVTID alone are more frequently ischemic but have a similar angiographic extent of CAD. Increased L/H ratio was correlated to both rest and postexercise LV volume, whereas increased LVTID was correlated only to postexercise LV volume.

Background: The ability of the size of a total myocardial perfusion defect (MPD) to detect extensive coronary artery disease (CAD) is currently suboptimal with exercise thallium 201 single photon emission computed tomography (SPECT). To improve its performance, exercise electrocardiography and indirect scintigraphic markers of extensive CAD were proposed (increased right ventricular Tl-201 uptake, lung-to-heart [L/H] ratio, and left ventricular transient ischemic dilation ratio). We aimed to determine the additive value of these criteria for the detection of extensive CAD., Methods and Results: The population included 338 patients who underwent exercise Tl-201 SPECT and coronary angiography. Patients were classified as having extensive CAD (left main, multivessel, or 1-vessel proximal left anterior descending CAD) or limited CAD (1-vessel disease other than proximal left anterior descending CAD or no CAD). First, Tl-201 SPECT provided higher diagnostic value than exercise electrocardiography. Second, age, percent target heart rate achieved, total MPD, and L/H ratio were independent predictors of extensive CAD. Third, visually estimated abnormal right ventricular Tl-201 uptake did not present additional information. Fourth, L/H ratio presented a higher diagnostic accuracy than left ventricular transient ischemic dilation ratio., Conclusions: With exercise Tl-201 SPECT, age, percent target heart rate achieved, total MPD, and L/H ratio were independent predictors of extensive CAD.