Assessment of Myocardial Viability in Patients With Chronic Coronary Artery Disease Rest–4-Hour–24-Hour 201Tl Tomography Versus Dobutamine Echocardiography

Background To date, late redistribution after resting 201Tl injection has not been evaluated. In addition, the concordance between resting 201Tl imaging and dobutamine echocardiography in identifying viable myocardium has not been assessed. Methods and Results Forty patients with coronary artery disease underwent rest–4-hour–24-hour 201Tl tomography and dobutamine echocardiography (5 to 10 μg·kg−1·min−1). Late redistribution occurred in 46 (21%) of 219 persistent defects at 4 hours. Systolic function and contractile reserve were similar among persistent defects at 4 hours with and without late redistribution. Contractile reserve was more frequent in segments with normal 201Tl uptake (59%), completely reversible defects (53%), or mild to moderate defects at 4 hours (56%) compared with severe defects (14%; P<.02 versus all). Of 105 hypokinetic segments, 99 (94%) were viable by 201Tl, and 88 (84%) showed contractile reserve. In contrast, of 155 akinetic segments, 119 (77%) were viable by 201Tl, but only 34 (...