The repolarization abnormalities, after radiofrequency catheter ablation (RFCA) of accessory pathway (AP) in patients with Wolff-Parkinson-White (WPW) syndrome, is commonly appeared in standard 12 lead electrocardiogram (ECG) as inverted T waves. We analyzed the serial ECGs after RFCA of AP in patients with WPW syndrome, in order to understand the repolarization abnormalities after RFCA.

The study patients were consisted of ninety two patients (mean age: 35 years old, male: 56 patients) out of 157 patients whose ECGs were taken at before, immediately after, one day, one, four, eight, twelve week (s) after RFCA from December 1992 to July 1997.

The seventy three patients (79%) out of ninety two patients showed the repolarization abnormalities and the thirteen patients (14%) showed normalization of secondary T wave changes immediately after RFCA. In contrast, six patients (7%) did not show any T wave changes after RFCA and they had left lateral AP. The lead that most frequently showed inverted T wave changes after RFCA was lateral lead (lead I, aVL) in case of left lateral AP and inferior lead (II, III, aVF) in case of other APs. The incidence of repolarization abnormalities after RFCA was significantly higher in patients whose preRFCA QRS duration is longer (≥0.12 sec). The concordance rate of repolarization abnormalities after RFCA was 86% (63 patients of 73 patients showing repolarization abnormalities after RFCA). The normalization of repolarization abnormalities after RFCA was acquired in sixty four patients (94%) out of sixty eight patients who showed repolarization abnormalities and followed up to twelve weeks after RFCA. The mean time interval to the normalization of repolarization abnormalities after RFCA was 4.3±3.2 weeks. The time interval to the normalization of repolarization abnormality after RFCA was not related with age, AP or preRFCA QRS duration.

The ECG lead, in which the repolarization abnormalities occurs after RFCA , is related with the location of the AP. The repolarization abnormalities after RFCA were more common in patients with longer preRFCA QRS duration. The repolarization abnormalities after RFCA could not be understood only by cardiac memory.