Introduction: Few non-invasive parameters have been identified for predicting atrial fibrillation (AF) recurrence after catheter ablation (CA). This study aimed to assess the association between AF recurrence and atrial late potentials (ALP) measured using P-wave signal-averaged electrocardiography (P-SAECG). Methods and results: Consecutive patients with paroxysmal AF who underwent first CA at our institution between August 2015 and August 2019 were enrolled. P-SAECG was performed before CA. Two ALP parameters were evaluated: root mean square voltage during the terminal 20 ms (RMS 20) and P-wave duration (PWD). Positive ALP was defined as an RMS 20 <2.2 µV and/or a PWD >115 ms. Patients were divided into the Recurrence and Non-recurrence groups based on AF recurrence at the 1-year follow-up after CA. Of 190 patients (age: 65±11 years, 37% women) enrolled in this study, 21 (11%) had AF recurrence. Positive ALP rate was significantly higher in the Recurrence group than in the Non-Recurrence group (86% vs. 64%, P=0.04) despite there being no differences in other baseline characteristics between the two groups. In the multivariate analysis, positive ALP was an independent predictor of AF recurrence (odds ratio: 3.83, 95% confidence interval: 1.05–14.1, P=0.04). Conclusion: Positive ALP on pre-CA P-SAECG was associated with AF recurrence after CA.

Introduction The incidence of new-onset atrial high-rate episode (AHRE) is higher among patients with cardiac implantable electronic devices (CIEDs) than in the general population. We sought to elucidate the clinical factors including P-wave dispersion (PWD) in sinus rhythm associated with AHRE in CIED patients. Methods and results One hundred one patients with newly implanted CIEDs from 2010 to 2014 at our institute were included. PWD was measured at the time of device implantation via a body-surface electrocardiogram. AHRE was defined as any episode of sustained atrial tachyarrhythmia (>170 bpm) recorded in the device’s memory. Patients were divided into an AHRE group (n=34) and non-AHRE group (n=67) in accordance with the presence or absence of AHRE within one year of device implantation and compared. The mean age was 75 ± 11 years old. A greater incidence of sick sinus syndrome (p=0.05) and longer PWD (62.6 ± 13.1 vs. 38.2 ± 13.9 ms; p<0.0001) were apparent in the AHRE group. Multivariate analysis revealed that PWD was an independent predicting factor for new-onset AHRE (odds ratio: 1.11; 95% confidence interval: 1.06–1.17; p<0.0001). In the logistic regression analysis, the receiver-operating characteristic curve (area under the curve: 0.90; p<0.001) suggested the best cutoff value for PWD was 48 mm, achieving a sensitivity of 73.8% and specificity of 77.9%. Conclusion PWD is a simple but feasible predictor for new-onset AHRE in patients with cardiac implantable electronic devices.

Background: Local impedance (LI) can indirectly measure catheter contact and tissue temperature during radiofrequency catheter ablation (RFCA). However, data on the effects of catheter contact angle on LI parameters are scarce. This study aimed to evaluate the influence of catheter contact angle on LI changes and lesion size with 2 different LI-sensing catheters in a porcine experimental study. Methods: Lesions were created by the INTELLANAV MiFi™ OI (MiFi) and the INTELLANAV STABLEPOINT™ (STABLEPOINT). RFCA was performed with 30 watts and a duration of 30 seconds. The CF (0, 5, 10, 20, and 30 g) and catheter contact angle (30°, 45°, and 90°) were changed in each set (n=8 each). The LI rise, LI drop, and lesion size were evaluated. Results: The LI rise increased as CF increased. There was no angular dependence with the LI rise under all CFs in the MiFi. On the other hand, the LI rise at 90° was lower than at 30° under 5 and 10 g of CF in STABLEPOINT. The LI drop increased as CF increased. Regarding the difference in catheter contact angles, the LI drop at 90° was lower than that at 30° for both catheters. The maximum lesion widths and surface widths were smaller at 90° than at 30°, whereas there were no differences in lesion depths. Conclusion: The LI drop and lesion widths at 90° were significantly smaller than those at 30°, although the lesion depths were not different among the 3 angles for the MiFi and STABLEPOINT.

Introduction: The impact of catheter ablation for atrial fibrillation (AF) on cardiovascular events and mortality is controversial. We investigated the impact of sinus rhythm maintenance on major adverse cardiac and cerebrovascular events after AF ablation from a Japanese multicenter cohort of AF ablation. Methods and Results: We investigated 2737 consecutive patients (25.6% female, mean age 63.4 ± 10.3 years) who underwent a first catheter ablation for AF from the Atrial Fibrillation registry to Follow the long-teRm Outcomes and use of aNTIcoagulants aftER Ablation (AF Frontier Ablation Registry). The primary endpoint was a composite of stroke, transient ischemic attack, cardiovascular events, and all-cause death. During a mean follow-up of 25.2 months, 2070 (75.6%) patients were free from AF after catheter ablation, and the primary composite endpoint occurred in 122 (4.5%) patients. The AF nonrecurrence group had a significantly lower incidence of the primary endpoint (1.7 per 100 person-years) compared with the AF recurrence group (3.2 per 100 person-years; P = 0.001). The multivariate analysis revealed that freedom from AF (hazard ratio 0.57; 95% confidence interval 0.39–0.83; P = 0.003) was independently associated with the incidence of the composite event.¬¬ Conclusion: In the multicenter cohort of AF ablation, sinus rhythm maintenance after catheter ablation was independently associated with lower rates of major adverse cardiac and cerebrovascular events.