Irrigated-tip vs. conventional-tip catheters for primary ablation of posteroseptal and right free-wall accessory pathways: a prospective randomized study.

BACKGROUND: The use of irrigated-tip catheters enables elimination of almost all accessory pathways (APs) resistant to standard radiofrequency ablation (RFA). However, efficacy of irrigation catheter technology in the initial AP ablation has not been studied systematically yet. OBJECTIVES: We tested whether the externally irrigated-tip catheters are more effective than the conventional-tip catheters for initial RFA of the posteroseptal and right free-wall APs, i.e., where application of the conventional RFA is expected to have a lower success rate. METHODS: Fifty consecutive patients (39 +/- 12 years, 32 males), who were subjected to primary catheter-ablation of the posteroseptal or right free-wall AP were randomly assigned to RFA with an externally irrigated-tip catheter (group I, n = 25; 45 degrees C/40 W outside the coronary sinus (CS) and 45 degrees C/30 W inside the CS) or a conventional-tip catheter (group C, n = 25; 60 degrees C/60 W outside and 55 degrees C/35 W inside the CS). RESULTS: No significant difference was identified between groups I and C with respect to acute success rate (88% vs. 96%), number of radiofrequency applications (6.8 +/- 4.7 vs. 6.1 +/- 4.3), RFA time (373 +/- 242 sec vs 365 +/- 241 sec), energy (11,022 +/- 7833 J vs. 12,870 +/- 11,414 J), fluoroscopy time (669 +/- 443 sec vs. 789 +/- 578 sec) and recurrence rate (18.2% vs. 16.7%). The only complication was encountered in group I, manifested as AV-block I-II degree after elimination of the right posteroseptal AP. CONCLUSIONS: Irrigated-tip catheters are not more efficient than conventional catheters in initial RFA of the posteroseptal and right free-wall APs. Therefore, the use of irrigated-tip catheters is justifiable only for ablation of the APs resistant to previously attempted conventional RFA.

[The role of the accessory pathway radiofrequency catheter ablation in the secondary prevention of the malignant tachyarrhythmias in patients with Wolff-Parkinson-White syndrome].

BACKGROUND/AIM: The occurrence of atrial fibrillation (AF) in the presence of an accessory pathway (AP) that conducts rapidly is potentially lethal because the rapid ventricular response may lead to ventricular fibrillation (VF). The aim of the study was to determine long-term efficacy of AP catheter-ablation using radiofrequency (RF) current in secondary prevention of VF in WPW patients. METHODS: Study included a total of 192 symptomatic WPW patients who underwent RF catheter-ablation of AP in our institution from 1994 to 2007 and were available for clinical follow-up for more than 3 months after procedure. RESULTS: Before ablation, VF was recorded in total of 27 patients (14.1%). In 14 of patients (51.9%) VF was the first clinical manifestation of WPW syndrome. A total of 35 VF episodes were identified in 27 patients. The occurence ofVF was preceded by physical activity or emotional stress in 17.1% of cases, by alcohol abuse in 2.9% and by inappropriate intravenous drug administration in 28.6%. In addition, no clear precipitating factor was identified in 40% of VF cases, while informations about activities preceding 11.4% of VF episodes were not available. The follow-up of 5.7 +/- 3.3 years was obtained in all of 27 VF patients. Of the 20 patients who underwent successful AP ablation, all were alive, without syncope or ventricular tachyarrhythmias during long-term follow-up. In 4 of 7 unsuccessfully treated patients, recurrence of supraventricular tachycardia and/or preexcited atrial fibrillation were recorded; one of these patients suddenly died of VF, 6 years after procedure. CONCLUSION: In significant proportion of WPW patients, VF was the first clinical manifestation of WPW syndrome, often precipitated by physical activity, emotional stress or inappropriate drug administration. Successful elimination of AP by percutaneous RF catheter-ablation is highly effective in secondary prevention of life-threatening tachyarrhythmias in patients with ventricular preexcitation.