Abstract
To assess the salvage effect on ischemic myocardium we studied 42 patients with ischemic heart disease by adenosine triphosphate (ATP) stress thallium (Tl) -201 and 123I-β-methyl-phenylpentadecanoic acid (I-BMIPP) dual single-photon emission computed tomography (SPECT) imaging before and one month after revascularization. We analyzed : (1) the QTc (corrected QT) interval dispersion ; (2) the redistribution in ATP-SPECT before revascularization ; and (3) the Tl/BMIPP discrepancy before and one month after revascularization. BMIPP and Tl-201 defects were scored in 9 segments of the left ventricle. The total defect score (TDS) was defined as the sum of the defect scores. Results : (1) There were correlations between both the QTc dispersion (QTD) and the TDS of the ATP-SPECT before and after revascularization. (2) Revascularization decreased the ATP-induced QTc dispersion and improved left ventricular ejection fraction (LVEF) (from 54.3 ± 14.1 to 63.1 ± 19.2, p <.0001) in redistribution (on Ti-SPECT perfusion imaging) (+) patients before revascularization, compared with no significant change in redistribution (-) patients. (3) Before revascularization there was a significant increase in the QTc dispersion during ATP infusion in the group in which Tl/BMIPP discrepancy was prolonged compared to the group in which the Tl/BMIPP discrepancy improved (69 ± 22 versus 78 ± 25, p= .0003) . Conclusions : These findings suggest that ATP-induced changes in the QTD may aid in evaluation of the salvage effect on the ischemic myocardium after revascularization.
