ASSESSMENT OF MYOCARDIAL VIABILITY IN PATIENTS WITH CHRONIC CORONARY-ARTERY DISEASE - REST-4-HOUR-24-HOUR TL-201 TOMOGRAPHY VERSUS DOBUTAMINE ECHOCARDIOGRAPHY

Background To date, late redistribution after resting Tl-201 injection has not been evaluated. In addition, the concordance between resting Tl-201 imaging and dobutamine echocardiography in identifying viable m yocardium has not been assessed Methods and Results Forty patients wit h coronary artery disease underwent rest-4-hour-24-hour Tl-201 tomogra phy and dobutamine echocardiography (5 to 10 mu g . g(-1). min(-1)). L ate redistribution occurred in 46 (21%) of 219 persistent defects at 4 hours. Systolic function and contractile reserve were similar among p ersistent defects at 4 hours with and without late redistribution. Con tractile reserve was more frequent in segments with normal Tl-201 upta ke (59%), completely reversible defects (53%), or mild to moderate def ects at 4 hours (56%) compared with severe defects (14%); P<.02 versus all). Of 105 hypokinetic segments, 99 (94%) were viable by Tl-201, an d 88 (84%) showed contractile reserve. In contrast, of 155 akinetic se gments, 119 (77%) were viable by Tl-201, but only 34 (22%) had contrac tile reserve. Concordance between Tl-201 and dobutamine was 82% in hyp okinetic segments but 43% in akinetic segments. In 109 revascularized segments, positive accuracy for functional recovery was 72% for Tl-201 and 92% for dobutamine whereas negative accuracy was 100% and 65%, re spectively. Sensitivity was 100% for Tl-201 and 79% for dobutamine. Co nclusions Late redistribution occurs in one fifth of persistent defect s at 4 hours, and it does not correlate to systolic function or contra ctile reserve. Dobutamine and Tl-201 yield concordant information in t he majority of hypokinetic segments, whereas concordance is low in aki netic segments. Dobutamine demonstrates higher positive accuracy and s ensitivity in predicting recovery of dysfunctional myocardium, whereas Tl-210 shows higher negative predictive accuracy but reduced positive accuracy.