Backgrounds Ablation index (AI) is useful to complete circumferential pulmonary vein isolation (CPVI) for atrial fibrillation (AF), but the role of radiofrequency power in AI‐guided CPVI remains to be elucidated. Methods We investigated 60 patients with AF undergoing AI‐guided CPVI (mean age, 66 ± 9 years; nonparoxysmal AF in 16). The first 40 patients were randomly assigned to low‐power (LP; n = 20) and medium‐power (MP; n = 20) groups and the following 20 patients to high‐power (HP). In LP, radiofrequency (RF) application was done at 30 W at the anterior and 20 W at the posterior left atrial (LA) wall, while in MP, it was at 40 W at the anterior and 30 W at the posterior LA wall. In HP, 50 W was applied at the anterior, 40 W at posterior LA wall and 30 W on the esophagus. At each ablation point, target AI was 400 at the anterior, 360 at the posterior LA wall, and 260 on the esophagus. Results The time to complete both‐side CPVI was shortest in HP (median, 40 minutes, interquartile range [IQR], 28‐63) followed by MP (58 [49‐83] minutes, P = .008 vs HP) and LP (84 [72‐93] minutes, P = .002 vs MP). Higher RF power application significantly increased first‐pass isolation rate (55% in LP, 80% in MP and 85% in HP, P = .002) and decreased LA‐PV reconnection rate (10% in LP, 8% in MP, and 0% in HP, P = .03). Conclusion In AI‐guided PVI, the HP RF application can shorten the time to complete PVI with a high rate of first‐pass isolation and a low rate of LA‐PV reconnection.

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ablation lesion. These novel technologies will promisingly bring new strategies of ablation and enhanced effectiveness and safety. Here, we review the previous reports on catheter ablation for persistent AF, and then introduce possible strategies for persistent AF ablation under concomitant use of the new technologies. Previous Reports on Ablation Strategies for Persistent AFPrior common procedures for persistent AF ablation include creation of linear lesions in the left atrium (LA) and focal ablation targeting complex fractionated electrograms (CFAEs Since the landmark study of Haïssaguerre et al demonstrating that the triggers initiating atrial fibrillation (AF) originate from the pulmonary veins (PVs), catheter ablation targeting PV has become an established strategy for paroxysmal AF. 1 The recognition that AF trigger sites were located within the PV antrum in the majority of cases led to extended, circumferential PV antrum isolation (PVAI) as an ablation procedure for AF. The recurrence of atrial tachyarrhythmias was reported to be significantly less in patients with large isolation areas around both ipsilateral PVs than in those with segmental PV isolation. 2 A recent study showed that, in patients with paroxysmal AF undergoing extended PVAI, the rate of late recurrence was lower than that previously reported with segmental or less extensive antral isolation. 3 Today, PVAI is the cornerstone of catheter-based therapies for paroxysmal AF. However, the success rates of catheter ablation in cases of persistent AF are significantly lower than those for paroxysmal AF. Progressive atrial remodeling in persistent AF has been regarded as a reason for the low efficacy of the treatment in persistent AF. Therefore, additional ablation strategies for modifying and eliminating the AF-sustaining atrial substrate have been developed and challenged.Recently, there has been technological progress in both 3D mapping systems and ablation catheters, which enable us to create precise high-resolution mapping and a durable Pulmonary vein (PV) antrum isolation (PVAI) is effective in treating paroxysmal atrial fibrillation (AF) but is less so for persistent AF. A recent randomized study on the ablation strategies for persistent AF demonstrated that 2 common atrial substrate modifications, creation of linear lesions in the left atrium and ablation of complex fractionated electrogram sites, in addition to PVAI did not improve the outcome compared with stand-alone PVAI, suggesting the necessity of a more individualized, selective approach to persistent AF. There are emerging technologies, including high-resolution mapping with the use of multi-electrode catheter and auto mapping system and contact force (CF) guide ablation; the former allows rapid and accurate confirmation of the completeness of PVAI, and the latter enhances the achievement of durable ablation lesions more securely. Ablation for fibrotic area(s) has been proposed as a new approach for substrate modification, and high-resolution mapping is useful to define the area ...

Background:The impact of high-power radiofrequency (RF) application in ablation index (AI)-guided atrial fibrillation (AF) ablation has not been elucidated. Methods and Results:We investigated 1,333 patients undergoing first AF ablation (median age 68 years; interquartile range [IQR] 61-73 years). The first 301 patients underwent AI-guided conventional power RF application (CP group), whereas the following 1,032 patients underwent high-power RF application (HP group). The minimum AI target values were 400, 360, and 260 at the left atrial anterior wall, posterior wall, and esophagus, respectively. RF power in the CP group was 30-40, 20-25, and 20 W at the anterior wall, posterior wall, and esophagus, respectively, compared with 50, 40, and 25, respectively, in the HP group. Procedure time was shorter in the HP than CP group (median 153 vs. 180 (IQR 152-229) min; P<0.0001). The percentage of first-pass pulmonary vein isolation (69% vs. 73%; P=0.07) and all procedure-related complications (2.0% vs. 3.4%; P=0.19) was similar. Kaplan-Meier analysis showed similar recurrence-free survival (RFS) for all AF types. Respective 1-year RFS in the CP and HP groups was 82% and 87% in paroxysmal AF, 78% and 82% in persistent AF, and 59% and 58% in long-standing persistent AF. Conclusions:In AI-guided AF ablation, high-power RF application shortens the procedure time without increasing complications and with similar outcomes.

S-ICD is a safe and effective alternative to conventional TV-ICD. The long-term safety and efficacy of the S-ICD need further investigation.

Purpose Localization of the esophagus and the left atrium (LA) posterior wall thickness (LAPWT) should be taken into account when delivering radiofrequency energy. To validate the visualization of the esophagus and analyze LAPWT by ICE advanced into the LA in patients with atrial fibrillation (AF) undergoing ablation index (AI)-guided pulmonary vein (PV) isolation. Methods In 73 patients (mean age, 68 ± 12; paroxysmal AF in 45), a 3-dimensional (3D) esophagus image was created with CARTO Soundstar Ⓡ and its location was compared with contrast esophagography saved in Carto UNIVU™. LAPWT adjacent to the esophagus was measured at 4 levels: left superior PV (LSPV), intervenous carina (IC), left inferior PV (LIPV), and LIPV bottom. A target AI value was 260 (25 W power) on the esophagus demonstrated by ICE. Results All patients had the esophagus posterior to the left PV antrum. Creating a 3D esophagus and measurement of LAPWT with ICE was done without any complications. ICE esophagus image was completely overlapped with contrast esophagography. LAPWT (mm) was 2.8 (interquartile range, 2.5-3.2), 2.2 (1.9-2.5), 1.9 (1.8-2.1), and 2.1 (1.9-2.4) for LSPV, IC, LIPV, and LIPV bottom, respectively, while LA roof thickness was 3.2 (2.9-3.6) (P < 0.0001 by ANOVA). No residual conduction gap on the esophagus after the first circumferential PV isolation was found in 64 of 73 (88%) patients. Conclusions ICE inserted into the LA can reliably locate and display the esophagus and its relationship to the LA. LAPWT was the thinnest at the LIPV level. AI-guided ablation targeting at AI value 260 on the esophagus seemed to be effective.

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Ivabradine increases stroke volume, but does not have a negative impact on blood pressure (BP). Thus, a patient with low BP can benefit from treatment with ivabradine. A 72-year-old Japanese woman with asthma and chronic bronchitis presented with dyspnea. Her heart rate (HR) was 126 beats per minute and an electrocardiogram showed sinus tachycardia. The chest X-ray showed cardiomegaly and pulmonary congestion. A transthoracic echocardiogram (TTE) showed reduced left ventricular ejection function (LVEF) and severe functional mitral regurgitation (MR). We diagnosed her with inappropriate sinus tachycardia (IST) and heart failure (HF) due to tachycardia-induced cardiomyopathy. After resolving the pulmonary congestion with diuretics, we administered a minimum dose of bisoprolol, which resulted in re-exacerbation of the HF. Because IST was persistent, we initiated treatment with ivabradine. As soon as ivabradine was started, the HR decreased, the BP gradually increased, and HF compensation was achieved. Bisoprolol was continued and losartan was started. In summary, we used ivabradine for a patient with tachycardia, low BP, a low LVEF, and severe MR. By optimizing the medical therapy, exercise tolerance improved and she was discharged. The serum brain natriuretic peptide was significantly reduced and TTE showed an improved LVEF and reduced MR. < Learning objective: We managed a patient who had low blood pressure (BP) due to tachycardia, reduced left ventricular ejection function (LVEF), and severe mitral regulation (MR). In this case, ivabradine had a novel effect; specifically, heart rate was reduced and BP increased. As a result of the drug effects, we could prescribe a renin-angiotensin-system inhibitor. With optimal medical therapy, LVEF was restored and functional MR was reduced. In similar cases, ivabradine can be a key drug for medical therapy of heart failure.>