Efficacy and safety of an irrigated-tip catheter for the ablation of accessory pathways resistant to conventional radiofrequency ablation

Background-Radiofrequency catheter ablation of accessory pathways (APs) is very effective in all but a minority of patients. We examined the usefulnes s and safety of irrigated-tip catheters in treating patients with APs resis tant to conventional catheter ablation. Methods and Results-Among 314 APs in 301 consecutive patients, conventional ablation failed to eliminate AP conduction in 18 APs in 18 patients (5.7%) , 6 of which were located in the left free wall, 5 in the middle/posterior- septal space, and 7 inside the coronary sinus (CS) or its tributaries. irri gated-tip catheter ablation was subsequently performed with temperature con trol mode (target temperature, 50 degreesC), a moderate saline flow rate (1 7 mL/min), and a power limit of 50 W (outside CS) or 20 to 30 W (inside CS) at previously resistant sites. Seventeen of the 18 resistant APs (94%) wer e successfully ablated with a median of 3 applications using irrigated-tip catheters, A significant increase in power delivery was achieved (20.3+/-11 .5 versus 36.5+/-8.2 W; P<0.01) with irrigated-tip catheters, irrespective of the AP location, particularly inside the CS or its tributaries. No serio us complications occurred. Conclusions-Irrigated-tip catheter ablation is safe and effective in elimin ating AP conduction resistant to conventional catheters, irrespective of th e location.