Low Energy Direct Current Ablation in Patients with the Wolff-Parkinson-White Syndrome: Clinical Outcome According to Accessory Pathway Location

Forty-five patients with (he Wolff-Parkinson-White syndrome underwent direct current (DC) ablation using a low energy power source (Cardiac Recorders). Anodal shocks of 10–40 joules were given to either a 6 French quadri polar catheter (Bard), a 7 French bipolar contoured catheter (Bard), or a 7 French deflectable catheter with a 4-mm distal electrode (Mansfield). The indifferent electrode consisted of a large patch that was positioned under the left scapula. There were 26 males and 19 females, with a mean age of 34 years (range 9–67), Accessory pathways were located in the left free wall in 30 patients (67%) and were posteroseptal in 15 patients (33%). The shortest ventriculoatrial interval during mapping (89 ± 21 msec), the mean cumulative amount of energy per patient (322 ± 283 joules), and the mean CK-MB rise (45 ± 30 units, normal 0–30 units) were not significantly different between both groups. Ablation was successful in 29/30 patients (97%) with a left free-wall accessory pathway, and in 13/15 patients (87%) with a posteroseptal accessory pathway. All three patients with failure of ablation had multiple accessory pathways, and two of these patients had Ebstein's anomaly. Palients with left free-wall and posteroseptal accessory pathways, respectively, differed significantly in terms of: total session time (4.1 ± 1 hours vs 5.3 ± 1.3, p = 0.0001), total procedure lime for ablation (2.6 ± 0.8 hours vs 3.2 ± 1.2, P = 0.02), and fluoroscopy time (46 ± 24 min vs 64 ± 29. P = 0.006). In 13 patients (29%) with a concealed accessory pathway, these variables were not significantly different from patients with overt preexcifation. In conclusion, low energy DC ablation can successfully ablate accessory pathways with a high success rate (93%). Procedure and fluoroscopy time are not related to the type of accessory pathway (overt vs concealed), but vary significantly according to accessory pathway location—left free-wall accessory pathways require shorter sessions and minutes of fiuoroscopy for successful ablation.