Catheter-induced mechanical trauma to accessory pathways during radiofrequency ablation: Incidence, predictors and clinical implications

OBJECTIVES. To evaluate the incidence, predictors and clinical implications of nonintentionally catheter-induced mechanical trauma to accessory pathwa ys during radiofrequency ablation procedures. BACKGROUND. Data on the incidence and significance of catheter-induced trau ma to accessory pathways are scarce. METHODS. Consecutive patients (n = 381) undergoing radiofrequency ablation of accessory pathways at two different institutions were closely monitored for appearance of mechanical block of accessory pathways during catheter ma nipulation. RESULTS. Mechanical trauma to accessory pathways was observed in 37 (9.7%) patients. According to a multivariate analysis, the only independent variab le associated with this phenomenon was the anatomical pathway location (p = 0.0001). The incidence of trauma of either right anteroseptal (38.5%) or r ight atriofascicular pathways (33.3%) was significantly greater than that o f pathways (less than or equal to 10%) at all remaining locations (p < 0.00 01). The duration of conduction block observed ranged from less than or equ al to 1 min to >30 min in 19% and 35% of patients, respectively. "Immediate " application of radiofrequency pulses at sites of mechanical block (<1 min after occurrence) was associated with a 78% long-term success rate at foll ow-up. This contrasted with a 25% long-term success rate in patients in who m pulses were delivered 30 min after occurrence of block ("delayed pulses") . Finally, in 24% of patients persistent trauma-induced conduction block le d to discontinuation of the ablation procedure. CONCLUSIONS. Trauma to accessory pathways is more common than previously re cognized and frequently results in prolongation or discontinuation of the a blation procedure and in lower success rates. The only independent predicto r of catheter-trauma to accessory pathways is the pathway location. (C) 199 9 by the American College of Cardiology.