Effect of Coronary Angioplasty on QT and JT Dispersion

Kim, Bum Soo; Kang, Jin Ho; Lee, Seung Won; Shim, Sung Choon; Cho, Young Kyun; Lee, Man Ho; Park, Jung Ro

Abstract

BACKGROUND
QT dispersion, reflecting inhomogenous ventricular repolarization, increases in myocardial ischemia. In addition, Many studies reported that prolonged QT dispersion reduced to normal after reperfusion treatment. We have carried out this study to evaluate the QT and JT dispersion before and after the angioplasty in patients with coronary artery diseases. METHOD AND MATERIALS: Seventy-two patients (55 men and 17 women:18 acute myocardial infarction, 9 unstable angina and 45 stable angina) who underwent percutaneous transluminal coronary angioplasty were evaluated. Standard 12-lead electrocardiograms were recorded 24 hours before and 24 hours after angioplasty at a paper speed of 25 mm/sec.
RESULTS
There was no significant change in heart rate or the maximum or minimum QT interval after angioplasty. QT dispersion significantly decreased after angioplasty (p<0.05). And QTc dispersion (QTcd) also similary reduced (p<0.01). JT dispersion (JTc) and JTc dispersion (JTcd) were not changed significantly. There were significant reduction in QTd and QTcd in the group of patients without acute myocardial infarction (p=0.005, 0.004, respectively) but not in JTd and JTcd. However, in patients with acute myocardial infarction, all four dispersion were not reduced significantly. And in patients with multivessel angioplasty, there were significant reduction of QTd, QTcd, JTd and JTcd (p=0.016, 0.014, 0.036, 0.030, respectively).
CONCLUSIONS
As changes in QT and JT dispersion reflect successful reperfusion by angioplasty, they can be accepted as promising test for assessing the effectiveness of angioplasty clinically. However the methodology still has several unresolved issues and larger, prospective clinical studies are needed.