We evaluated whether an irrigated contact force–sensing catheter would improve the safety and effectiveness of radiofrequency ablation of premature ventricular contractions originating from the right ventricular outflow tract. We retrospectively reviewed the charts of patients with symptomatic premature ventricular contractions who underwent ablation with a contact force–sensing catheter (56 patients, SmartTouch) or conventional catheter (59 patients, ThermoCool) at our hospital from August 2013 through December 2015. During a mean follow-up of 16 ± 5 months, 3 patients in the conventional group had recurrences, compared with none in the contact force group. Complications occurred only in the conventional group (one steam pop; 2 ablations suspended because of significantly increasing impedance). In the contact force group, the median contact force during ablation was 10 g (interquartile range, 7–14 g). Times for overall procedure (36.9 ± 5 min), fluoroscopy (86.3 ± 22.7 s), and ablation (60.3 ± 21.4 s) were significantly shorter in the contact force group than in the conventional group (46.2 ± 6.2 min, 107.7 ± 30 s, and 88.7 ± 32.3 s, respectively; P <0.001). In the contact force group, cases with a force-time integral <560 gram-seconds (g-s) had significantly longer procedure and fluoroscopy times (both P <0.001) than did those with a force-time integral ≥560 g-s. These findings suggest that ablation of premature ventricular contractions originating from the right ventricular outflow tract with an irrigated contact force–sensing catheter instead of a conventional catheter shortens overall procedure, fluoroscopy, and ablation times without increasing risk of recurrence or complications.

BackgroundThe coronary sinus (CS), as a junction of the atria, contributes to atrial fibrillation (AF) by developing unstable reentry, and isolating the atria by ablation at the CS could terminate AF. The present study evaluated whether AF activities at the CS in a subset of patients contributed to AF maintenance and predicted clinical outcome of ablation.Methods and ResultsWe studied 122 consecutive patients who had a first‐time radiofrequency ablation for persistent AF. Bipolar electrograms were obtained from multiple regions of the left atrium by a Lasso mapping catheter before ablation. Pulmonary vein isolation terminated AF in 12 patients (9.8%). Sequential stepwise ablation was conducted in pulmonary vein isolation nontermination patients and succeeded in 22 patients (18%). In the stepwise termination group, AF frequency in the proximal CS (CSp) was significantly higher (10.2±2.1 Hz versus 8.3±1.8 Hz, P<0.001), and the ratio of distal CS (CSd) to proximal CS (CSd/CSp ratio, 56.6%±10.11% versus 70.7%±9.8%, P<0.001) was significantly lower than that in the nontermination group. The stepwise logistic regression analysis indicated that the CSd/CSp ratio was an independent predictor with an odds ratio of 1.131 (95%CI 1.053‐1.214; P=0.001). With a cutoff of 67%, the patients with lower CSd/CSp ratios had significantly better index and long‐term outcomes than those with higher ratios during a follow‐up of 46±18 months.ConclusionsRapid repetitive activities in the musculature of the proximal CS may contribute to maintenance of AF after pulmonary vein isolation alone in persistent AF. A cutoff at 67%, of the CSd/CSp frequency ratio might be an indicator to stratify the subset of patients who might benefit from CS ablation.