Posterior Wall Ablation for Persistent Atrial Fibrillation: Very High-Power Short-Duration versus Standard Power Radiofrequency Ablation

Background Posterior wall ablation(PWA) is commonly added to pulmonary vein isolation(PVI) during catheter ablation(CA) of persistent atrial fibrillation(AF). Objective We sought: 1)to compare PVI plus PWA using very high-power, short-duration(vHPSD) versus standard-power (SP), ablation index-guided CA among consecutive patients with persistent AF; 2)to determine the voltage correlation between microbipolar and bipolar mapping in AF. Methods We compared 40 patients undergoing PVI plus PWA using vHPSD to 40 controls receiving PVI plus PWA using SP. The primary efficacy endpoint was recurrence of atrial tachyarrhythmias after a 3-month blanking period. The primary safety outcome was a composite of major complications within 30 days after CA. In the vHPSD group, high-density mapping of the PW was performed using both a multipolar catheter, and microelectrodes on the ablation catheter’s tip. Results Posterior wall isolation was more commonly obtained with vHPSD compared to SP ablation(98%vs.75%,p=0.007), despite shorter procedure and fluoroscopy times(p<0.001). Survival free from recurrent atrial tachyarrhythmias at 18 months was 68% and 47% in the vHPSD and SP groups, respectively(log-rank p=0.071), without major adverse events. The vHPSD approach was significantly associated with reduced risk of recurrent AF at multivariable analysis(HR,0.39,p=0.030). Microbipolar voltage cutoffs of 0.71mV and 1.69mV predicted minimum bipolar values of 0.16mV and 0.31mV in AF, respectively, with accuracies of 0.67 and 0.88. Conclusion VHPSD PWA plus PVI may be faster and as safe as SP CA among patients with persistent AF, with a trend for superior efficacy. Adapted voltage cutoffs should be used for identifying atrial low-voltage areas with microbipolar mapping.