QT dispersion (QTd) represents the inhomogeneity of ventricular repolarization and has been suggested to predict ventricular arrhythmia in patients with coronary artery disease (CAD). This study investigates the short-term effect of percutaneous transluminal coronary angioplasty (PTCA) on QTd in patients with CAD and no history of previous myocardial infarct.

In 84 angina patients (65 men and 19 women, mean age of 58.3±9.0 yeras) who underwent successful PTCA of single coronary artery, ECG was checked in baseline, immediate, 1day and 1 month after PTCA. QTd and corrected QTd (c-QTd) were measured in these ECGs by digitizer.

PTCA was performed at left anterior descending artery (LAD) in 56, left circumflex artery (LCx) in 12 and right coronary artery (RCA) in 16 patients. Mean and standard error of QTd (c-QTd) at baseline, immediate, 1day and 1month after PTCA was 51.3±4.2 (50.7±4.1), 54.2±4.5 (52.8±4.5), 47.7±4.3 (48.5±4.8) and 36.3±4.5 (37.5±4.6)msec, respectively. QTd and c-QTd significantly decreased at 1 month following PTCA. The difference was more prominent in pateints with LAD lesion than LCx or RCA lesion and independent of gender, severity of stenosis and use of beta-blockers.

QTd decreases in CAD patients with no history of myocardial infarct at 1 month following successful PTCA. This may facilitate a favorable recovery from inhomogenous repolarization. These findings call for long-term follow-up of QTd and the incidence of ventricular tachyarrhythmias and sudden death following successful PTCA.