Influence of Early Coronary Reperfusion on QT Interval Dispersion After Acute Myocardial Infarction

We studied the influence of early coronary reperfusion on QT interval dispersion in patients with acute myocardial infarction (MI). Tbere were 54 males and 18 females witb a mean age of 60 ± 10 years. Of the 51 patients with recanalization of the infarct related vessel in the recovery phase, 28 (group A) had early coronary reperfusion (5.5 ± 2.7 bours), 23 other patients (group B) were not confirmed with early coronary reperfusion. Twenty-one patients (group C) did not undergo recanalization of the infarct related vessel in the recovery phase. Corrected QT (QT_c) maximum, QT_c minimum, and QT_C dispersion calculated as tbe difference between the maximum and minimum QT_c intervals, were compared among these three groups at both acute and recovery phase. At the acute phase after MI, there were no significant differences in the QT_c maximum, QT_c minimum, QT dispersion, and QT_c dispersion among these three groups. At the recovery phase after MI, there were also no significant differences in the QTc maximum and QTc minimum. However, there were significant differences in the QT dispersion (0.035 ± 0.010 in group A, 0.049 ± 0.015 in group B, and 0.061 ± 0.031 s in group C, respectively; P = 0.0001), and QT_c dispersion (0.038 ± 0.012 in group A, 0.050 ± 0.015 in group B, and 0.063 ± 0.032 s in group C, respectively; P = 0.0003) among the three groups. Comparison of QT_c dispersion between acute and recovery phase revealed significant reduction from acute to recovery phase in group A. The number of premature ventricular contraction was lower in groups A and B than group C. In summary, early coronary reperfusion may reduce electrophysiological instability by reducing QT dispersion in the recovery phase after acute MI.