Secondary T Wave Changes in Patients with Wolff-Parkinson-White(WPW) Syndrome

ABSTRACT

OBJECTIVES: The purpose of this study is to evaluate the incidence of secondary T wave changes in WPW syndrome and the relation between the incidence of the secondary T wave changes and sex, age (duration of preexcitation), mean and maximal QRS duration (from the onset of delta wave to the end of S wave) of standard 12 lead electrocardiogram (ECG) and the site of accessory pathway (AP). The secondary purpose of this study is to evaluate the relation between the site of secondary T wave changes and the location of the AP. METHODS: Of the total 128 patients (pts) with WPW syndrome, standard 12 lead ECGs of 125 pts (mean age 35, male 71 pts) who were free from bundle branch block (n=2) and myocardial ischemia (n=1) were analyzed. The locations of Aps were divided into 4 categories (anterior, left lateral, posterior and right lateral) by intracardiac mapping. RESULTS: 82 (66%) pts of 125 pts showed secondary T wave changes. The incidence of secondary T wave changes was not related to sex or duration of preexcitation, but mean QRS duration (<0.12 46%, 0.12 88%, p<0.001), maximal QRS duration (<0.12 32%, 0.12 73%, p<0.001) and the site of AP (right 80%, left 54%, p=0.003). The most frequent lead showing secondary T wave changes in ECG was lateral (lead I, aVL) in pts with anterior (43%, 9 out of 21), posterior (50%, 25 out of 50) and right lateral (86%, 6 out of 7) AP. But, no secondary T wave change was found in most pts with left lateral (n=47) AP. CONCLUSION: The incidence of the secondary T wave changes in pts with WPW syndrome is high (66%). These changes are not related to sex and duration of preexcitation, but to the mean and maximal QRS duration during preexcitation and the location of the AP. The ECG lead showing secondary T wave changes in pts with WPW syndrome appears to be related to the location of the AP and the most frequent lead is I and aVL.