Background: Myocardial ischemia is one of several potential causes of increased QT dispersion(QTd) in patients with nonacute total coronary artery occlusions(TCOs). We sought to assess the effect of percutaneous revascularization(PCI) of TCO on QTd and the relationship between QTd and long- term vessel patency. Methods: Seventy patients enrolled in the TOSCA were analyzed. Patients were undergoing PCI of a TCO >72 hours’ duration. Two independent reviewers measured QTd from electrocardiograms done immediately before PCI(PRE), 12 to 18 hours after PCI(POST), and then at 6 months(6M). Follow- up angiography was performed at 6 months. Results: Mean QTd decreased from PRE(77± 29 milliseconds) to POST(66± 26 milliseconds, P< .001) and 6M(65± 25 milliseconds, P< .001). Patients with the same or longer QTd at 6 months compared with POST(POST ≤ 6M) had significantly higher risk of failed target- vessel patency(odds ratio 10.3, 95% CI 1.24- 84.8) than patients with QTd reduction at 6M versus POST values. Conclusion: Revascularization of TCO resulted in a decrease in QTd, which was sustained at 6M. This suggests that PCI to a TCO has a beneficial effect on stabilization of the underlying ischemic substrate. Furthermore, absence of QTd reduction at 6M versus POST was associated with increased risk of failed target- vessel patency.
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