Objectives: The primary objective was to assess the immediate and short-term impact of successful percutaneous coronary intervention (PCI) on QT dispersion (QT disp) and corrected QT dispersion (QTc disp). Secondarily, the impact of PCI on QT and QTc disp within different infarct-related arteries and the impact of successful PCI in these different arteries were evaluated.
Methods: Patients (n = 140, age 61.6 +/- 12.9, 69% male) undergoing direct primary PCI for acute MI were evaluated. Twelve-lead ECGs were obtained before (baseline), immediately after (0 h), 24hours after, and 3 days after PCI. The QT and QTc interval in each of the 12-leads were measured and the shortest interval was subtracted from the longest to derive the QT disp and QTc disp, respectively.
Results: Angiography showed blockages in the left anterior descending, right coronary artery, and circumflex in 37.1, 48.9, and 15.0% of patients, respectively. Overall, 97 patients achieved successful reflow. QT and QTc disp were significantly improved in the group with successful reflow at each follow-up time after PCI versus baseline and corresponding values in the unsuccessful reflow group. QT disp was improved among patients with successful reflow irrespective of which infarct artery was responsible for the acute myocardial infarction.
Conclusions: Successful reflow with PCI is associated with a rapid reduction in QT disp and QTc disp that is maintained for at least 3 days after the event. Conversely, unsuccessful reflow was not associated with significant reductions in QT or QTc disp.