RADIOFREQUENCY CATHETER ABLATION OF ACCESSORY ATRIOVENTRICULAR PATHWAYS - PRIMARY FAILURE AND RECURRENCE OF CONDUCTION

Objective-To identify possible factors associated with primary failure of radio-frequency ablation of accessory pathways or recurrence of ac cessory pathway conduction. Patients and methods-Radiofrequency ablati on of accessory pathways failed in 25 of 243 patients, and recurrence of accessory pathway conduction occurred in an additional 13 patients. Factors possibly related to primary failure and recurrence were analy sed. Results-Primary failure and recurrence were less frequent in pati ents with left sided pathways (7% v 19%; 4% v 24%; P = 0.04). The fact ors that might relate to primary failure included an unstable catheter position (seven patients), a possible epicardial pathway (six patient s), or misdiagnosis of accessory pathway location (two patients). The major factors for recurrence included the stability of the local atria l electrogram less than or equal to 0.5 together with the stability of the local ventricular electrogram less than or equal to 0.8, and prol onged time to pathway conduction block greater than or equal to 12 sec onds). Thirty one patients underwent repeat ablation which was success ful in 28. Conclusions-Primary failure and recurrence were more freque nt in patients with right sided pathways. An unstable catheter positio n and a possible epicardial pathway location are the main contributing factors for primary failure, while unstable local electrograms and pr olonged time to block are independent predictors for recurrence.