Randomized, Controlled Trial of the Safety and Effectiveness of a Contact Force-Sensing Irrigated Catheter for Ablation of Paroxysmal Atrial Fibrillation: Results of the TactiCath Contact Force Ablation Catheter Study for Atrial Fibrillation (TOCCASTAR) Study.

BACKGROUND: Contact force (CF) is a major determinant of lesion size and transmurality and has the potential to improve efficacy of atrial fibrillation ablation. This study sought to evaluate the safety and effectiveness of a novel irrigated radiofrequency ablation catheter that measures real-time CF in the treatment of patients with paroxysmal atrial fibrillation. METHODS AND RESULTS: A total of 300 patients with symptomatic, drug-refractory, paroxysmal atrial fibrillation were enrolled in a prospective, multicenter, randomized, controlled trial and randomized to radiofrequency ablation with either a novel CF-sensing catheter or a non-CF catheter (control). The primary effectiveness end point consisted of acute electrical isolation of all pulmonary veins and freedom from recurrent symptomatic atrial arrhythmia off all antiarrhythmic drugs at 12 months. The primary safety end point included device-related serious adverse events. End points were powered to show noninferiority. All pulmonary veins were isolated in both groups. Effectiveness was achieved in 67.8% and 69.4% of subjects in the CF and control arms, respectively (absolute difference, -1.6%; lower limit of 1-sided 95% confidence interval, -10.7%; P=0.0073 for noninferiority). When the CF arm was stratified into optimal CF (≥90% ablations with ≥10 g) and nonoptimal CF groups, effectiveness was achieved in 75.9% versus 58.1%, respectively (P=0.018). The primary safety end point occurred in 1.97% and 1.40% of CF patients and control subjects, respectively (absolute difference, 0.57%; upper limit of 1-sided 95% confidence interval, 3.61%; P=0.0004 for noninferiority). CONCLUSIONS: The CF ablation catheter met the primary safety and effectiveness end points. Additionally, optimal CF was associated with improved effectiveness. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov. Unique identifier: NCT01278953.

Radiofrequency catheter ablation of type 1 atrial flutter using large-tip 8- or 10-mm electrode catheters and a high-output radiofrequency energy generator: results of a multicenter safety and efficacy study.

OBJECTIVES: We studied the safety and efficacy of atrial flutter (AFL) ablation using 8- or 10-mm electrode catheters and a 100-W radiofrequency (RF) generator. BACKGROUND: Large-tip electrode catheters may be more effective for ablation of AFL. METHODS: There were 169 patients (age 61 +/- 12 years). Short-term end points were bidirectional isthmus block and no inducible AFL. After ablation, patients were seen at one, three, and six months, with event monitoring performed weekly and for any symptoms. Three quality-of-life (QOL) surveys were completed during follow-up. RESULTS: Short-term success was achieved in 158 patients (93%), with 12 +/- 11 RF applications. The efficacy of 8- and 10-mm electrodes was similar (p = NS). The number of RF applications (10 +/- 8 vs. 14 +/- 8) and ablation time (0.5 +/- 0.4 h vs. 0.8 +/- 0.6 h) were less with the 10- versus 8-mm electrode, respectively (p < 0.01). Of 158 patients with short-term success, 42 patients were not evaluated for success at six months because of study exclusions. Of 116 patients with short-term success evaluated at six months, 112 (97%) patients had no AFL recurrence. Of those without AFL recurrence at six months, 95% and 93% remained free of symptoms at 12 and 24 months, respectively. Ablation of AFL improved QOL scores (p < 0.05) and reduced anti-arrhythmic and rate-control drug use (p < 0.05). Complications occurred in 6 (3.6%) of 169 patients, but there were no deaths. CONCLUSIONS: Ablation of AFL with 8- or 10-mm electrode catheters and a high-power RF generator was safe and effective and improved QOL. The number and duration of RF applications were lower with 10- versus 8-mm electrode catheters.

Asymptomatic partial anomalous pulmonary venous return masquerading as pulmonary vein occlusion following radiofrequency ablation.

Recent advances in the field of cardiac electrophysiology have resulted in the rapid growth of radiofrequency ablation for treatment of arrhythmias. Pulmonary vein stenosis or occlusion is a rare, but well described adverse outcome. Fortunately, the concomitant evolution of multislice computed tomography (CT) scanners has provided an excellent non-invasive method of monitoring for this complication. We recently encountered a case on multislice CT that initially appeared to be a pulmonary vein occlusion related to the procedure, but on further evaluation was found to be an asymptomatic case of partial anomalous pulmonary venous return.