P.1. Supraventricular Arrhythmias

Use of body surface potential mapping (BSPM) in adult patients with Wolf-Parkinson-White syndrome (WPW) before and after radiofrequency ablation (RFA) of anomalous pathway (AP) is well known. The aim to evaluate the diagnostic ability of the BSPM in children with WPW. Methods BSPM was carried out in 23 children with WPW (age 14,1±2,6; 12 boys, 11 girls) before and after RFA. Cardiac System (Czech Republic) with ECG registration in 80 unipolar leads on the thorax surface, 12 standard and 3 orthogonal leads was used for BSM. We analyzed isopotential, isointegral and departure maps. Results initial BSPM with QRS isopotential maps analyzes were turned to account for the noninvasive localization of AP. 48% of patients had midseptal (2) or paraseptal (9) AP that are difficult to identify by non invasive methods. The locations obtained by BSPM were compatible with invasive locations with 83,3% accuracy. After RFA of AP, DI<-2 zone – the negative zone on STT departure integral maps was used as a noninvasive indicator of local electrical repolarization changes. The last were revealed in the projections of corresponding RFA zones with negative values of DI (−3,1±1,2), the average volume of negative DI region was 9,5%. BSPM was carried out in 4 pts 3 month after intervention and revealed significant reduction of indexes, characterizing the repolarization anomalies. Conclusions BSPM is a high-resolution noninvasive method for the children with WPW syndrome. It is helpful in topical diagnosis before RFA and assessment of the myocardial changes after RFA.