Safety and Effectiveness of Pulsed Field Ablation to Treat Atrial Fibrillation: One-Year Outcomes From the MANIFEST-PF Registry.

BACKGROUND: Pulsed field ablation is a novel nonthermal cardiac ablation modality using ultra-rapid electrical pulses to cause cell death by a mechanism of irreversible electroporation. Unlike the traditional ablation energy sources, pulsed field ablation has demonstrated significant preferentiality to myocardial tissue ablation, and thus avoids certain thermally mediated complications. However, its safety and effectiveness remain unknown in usual clinical care. METHODS: MANIFEST-PF (Multi-National Survey on the Methods, Efficacy, and Safety on the Post-Approval Clinical Use of Pulsed Field Ablation) is a retrospective, multinational, patient-level registry wherein patients at each center were prospectively included in their respective center registries. The registry included all patients undergoing postapproval treatment with a multielectrode 5-spline pulsed field ablation catheter to treat atrial fibrillation (AF) between March 1, 2021, and May 30, 2022. The primary effectiveness outcome was freedom from clinical documented atrial arrhythmia (AF/atrial flutter/atrial tachycardia) of ≥30 seconds on the basis of electrocardiographic data after a 3-month blanking period (on or off antiarrhythmic drugs). Safety outcomes included the composite of acute (<7 days postprocedure) and latent (>7 days) major adverse events. RESULTS: At 24 European centers (77 operators) pulsed field ablation was performed in 1568 patients with AF: age 64.5±11.5 years, female 35%, paroxysmal/persistent AF 65%/32%, CHA2DS2-VASc 2.2±1.6, median left ventricular ejection fraction 60%, and left atrial diameter 42 mm. Pulmonary vein isolation was achieved in 99.2% of patients. After a median (interquartile range) follow-up of 367 (289-421) days, the 1-year Kaplan-Meier estimate for freedom from atrial arrhythmia was 78.1% (95% CI, 76.0%-80.0%); clinical effectiveness was more common in patients with paroxysmal AF versus persistent AF (81.6% versus 71.5%; P=0.001). Acute major adverse events occurred in 1.9% of patients. CONCLUSIONS: In this large observational registry of the postapproval clinical use of pulsed field technology to treat AF, catheter ablation using pulsed field energy was clinically effective in 78% of patients with AF.

Very high-power short-duration catheter ablation for treatment of cardiac arrhythmias: Insights from the FAST and FURIOUS study series.

The QDOT MICRO™ Catheter is a novel open-irrigated contact force-sensing radiofrequency ablation catheter. It offers very high-power short-duration (vHPSD) ablation with 90 W for 4 s to improve safety and efficacy of catheter ablation procedures. Although the QDOT MICRO™ Catheter was mainly designed for pulmonary vein isolation (PVI) its versatility to treat atrial fibrillation (AF) and other types of arrhythmias was recently evaluated by the FAST and FURIOUS study series and other studies and will be presented in this article. Available study and registry data as well as case reports concerning utilization of the QDOT MICRO™ Catheter for the treatment of cardiac arrhythmias including AF, focal and macroreentry atrial tachycardia, typical atrial flutter by cavotricuspid isthmus block, premature ventricular contractions, and accessory pathways were reviewed and summarized. In summary, the QDOT MICRO™ Catheter showed safety and efficacy for PVI and is able to treat also other types of arrhythmias as is was recently evaluated by case reports and the FAST and FURIOUS studies.

Impact of pulsed field ablation on intraluminal esophageal temperature.

INTRODUCTION: Atrio-esophageal fistula after esophageal thermal injury (ETI) is one of the most devastating complications of available energy sources for atrial fibrillation (AF) ablation. Pulsed field ablation (PFA) uses electroporation as a new energy source for catheter ablation with promising periprocedural safety advantages over existing methods due to its unique myocardial tissue sensitivity. In preclinical animal studies, a dose-dependent esophageal temperature rise has been reported. In the TESO-PFA registry intraluminal esophageal temperature (TESO) changes in a clinical setting are evaluated. METHODS: Consecutive symptomatic AF patients (62 years, 67% male, 61% paroxysmal AF, CHA2 DS2 Vasc Score 2) underwent first-time PFA and were prospectively enrolled into our registry. Eight pulse trains (2 kV/2.5 s, bipolar, biphasic, x4 basket/flower configuration each) were delivered to each pulmonary vein (PV). Two extra pulse trains per PV in flower configuration were added for wide antral circumferential ablation. Continuous intraluminal esophageal temperature (TESO) was monitored with a 12-pole temperature probe. RESULTS: Median TESO change was statistically significant and increased by 0.8 ± 0.6°C, p < .001. A TESO increase ≥ 1°C was observed in 10/43 (23%) patients. The highest TESO measured was 40.3°C. The largest TESO difference (∆TESO) was 3.7°C. All patients remained asymptomatic considering possible ETI. No atrio-esophageal fistula was reported on follow-up. CONCLUSION: A small but significant intraluminal esophageal temperature rise can be observed in most patients during PFA. TESO rise over 40°C is rare. The clinical implications of the observed findings need to be further evaluated.

Venous vascular closure system vs. figure-of-eight suture following atrial fibrillation ablation: the STYLE-AF Study.

AIMS: Simplified ablation technologies for pulmonary vein isolation (PVI) are increasingly performed worldwide. One of the most common complications following PVI are vascular access-related complications. Lately, venous closure systems (VCSs) were introduced into clinical practice, aiming to reduce the time of bed rest, to increase the patients' comfort, and to reduce vascular access-related complications. The aim of the present study is to compare the safety and efficacy of using a VCS to achieve haemostasis following single-shot PVI to the actual standard of care [figure-of-eight suture and manual compression (MC)]. METHODS AND RESULTS: This is a prospective, multicentre, randomized, controlled, open-label trial performed at three German centres. Patients were randomized 1:1 to undergo haemostasis either by means of VCS (VCS group) or of a figure-of-eight suture and MC (F8 group). The primary efficacy endpoint was the time to ambulation, while the primary safety endpoint was the incidence of major periprocedural adverse events until hospital discharge. A total of 125 patients were randomized. The baseline characteristics were similar between the groups. The VCS group showed a shorter time to ambulation [109.0 (82.0, 160.0) vs. 269.0 (243.8, 340.5) min; P < 0.001], shorter time to haemostasis [1 (1, 2) vs. 5 (2, 10) min; P < 0.001], and shorter time to discharge eligibility [270 (270, 270) vs. 340 (300, 458) min; P < 0.001]. No major vascular access-related complication was reported in either group. A trend towards a lower incidence of minor vascular access-related complications on the day of procedure was observed in the VCS group [7 (11.1%) vs. 15 (24.2%); P = 0.063] as compared to the control group. CONCLUSION: Following AF ablation, the use of a VCS results in a significantly shorter time to ambulation, time to haemostasis, and time to discharge eligibility. No major vascular access-related complications were identified. The use of MC and a figure-of-eight suture showed a trend towards a higher incidence of minor vascular access-related complications.

Left atrial appendage closure in end-stage renal disease and hemodialysis: Data from a German multicenter registry.

BACKGROUND: Left atrial appendage closure (LAAC) has emerged as an alternative to oral anticoagulation (OAC) for stroke prevention in patients with atrial fibrillation (AF). OAC treatment has been proven feasible in mild-to-moderate chronic kidney disease (CKD). In contrast, the optimal antithrombotic management of AF patients with end-stage renal disease (ESRD) is unknown and LAAC has not been proven in these patients in prospective randomized clinical trials. OBJECTIVES: The objective of this study is to evaluate safety and efficacy of LAAC in patients with ESRD. METHODS: Patients undergoing LAAC were collected in a German multicenter real-world observational registry. A composite endpoint consisting of the occurrence of ischemic stroke/transient ischemic attack, systemic embolism, and/or major clinical bleeding was assessed. Patients with ESRD were compared with propensity score-matched patients without severe CKD. ESRD was defined as a glomerular filtration rate < 15 ml/min/1.73 m2 or chronic hemodialysis treatment. RESULTS: A total of 604 patients were analyzed, including 57 with ESRD and 57 propensity-matched patients. Overall, 596 endocardial and 8 epicardial LAAC procedures were performed. Frequency of major complications was 7.0% (42/604 patients) in the overall cohort, 8.8% (5/57 patients) in patients with ESRD, and 10.5% (6/57 patients) in matched controls (p = 0.75). The estimated event-free survival of the combined endpoint after 500 days was 90.7 ± 4.5% in patients with ESRD and 90.2 ± 5.5% in matched controls (p = 0.33). CONCLUSIONS: LAAC had comparable procedural safety and clinical efficacy in patients with ESRD and patients without severe CKD.

Very high-power short-duration ablation for pulmonary vein isolation utilizing a very-close protocol-the FAST AND FURIOUS PVI study.

AIMS: The very high-power short-duration (vHP-SD) radiofrequency (RF) ablation concept of atrial fibrillation (AF) treatment by pulmonary vein isolation (PVI) aims for safer, more effective, and faster procedures. Utilizing conventional ablation, the 'close protocol' has been verified. Since lesion formation of vHP-SD ablation creates wider but shallower lesions we adapted the close protocol to an individualized and tighter 'very-close protocol' of 3-4 mm of inter-lesion distance (ILD) at the anterior and 5-6 mm at the posterior aspect of the left atrium using vHP-SD only. Here, we evaluated the safety and efficacy of vHP-SD ablation for PVI utilizing a very-close protocol in comparison with standard ablation. METHODS AND RESULTS: A total of 50 consecutive patients with symptomatic AF were treated with a very-close protocol utilizing vHP-SD (vHP-SD group). The data were compared with 50 consecutive patients treated by the ablation-index-guided strategy (control group). The mean RF time was 352 ± 81 s (vHP-SD) and 1657 ± 570 s (control, P < 0.0001), and the mean procedure duration was 59 ± 13 (vHP-SD) and 101 ± 38 (control, P < 0.0001). The first-pass isolation rate was 74% (vHP-SD) and 76% (control, P = 0.817). Severe adverse events were reported in 1 (2%, vHP-SD) and 3 (6%, control) patients (P = 0.307). A 12-month recurrence-free survival was 78% (vHP-SD) and 64% (control, P = 0.142). PVI durability assessed during redo-procedures was 75% (vHP-SD) vs. 33% (control, P < 0.001). CONCLUSIONS: PVI solely utilizing vHP-SD via a very-close protocol provides safe and effective procedures with a high rate of first-pass isolations. The procedure duration and ablation time were remarkably low. A 12-month follow-up and PVI durability are promising.

Novel or established cryoballoon ablation system for pulmonary vein isolation: the prospective ICE-AGE-1 study.

AIMS: Catheter ablation with a cryoballoon (CB) provides effective and durable pulmonary vein (PV) isolation (PVI) associated with encouraging clinical outcome data. The novel POLARx CB incorporates unique features, which may translate into improved safety, efficacy, and outcomes. The ICE-AGE-1 study aimed to assess the efficacy, safety, and 1-year clinical follow-up of the POLARx CB in comparison to the Arctic Front Advance Pro CB (AF-CB4). METHODS AND RESULTS: A total of 103 consecutive patients with paroxysmal or persistent atrial fibrillation (AF) who underwent POLARx-based PVI (POLARx group) were prospectively enrolled and were compared to 102 consecutive patients previously treated with the AF-CB4 (AF-CB4 group). The mean age was 68.7 ± 10.2 (POLARx) and 65.7 ± 12 (AF-CB4, P = 0.0551) years. A total of 412 (POLARx) and 404 (AF-CB4) PVs were identified. All PVs, except for one PV in the POLARx group, were successfully isolated. A significant difference regarding the mean minimal CB temperature reached using the POLARx CB (-56.1 ± 8.3°C) and AF-CB4 (-46.9 ± 10.1°C) was observed (P < 0.0001). Real-time PVI was visualized in 71% of PVs in the POLARx group and 46% of them in the AF-CB4 group (P < 0.001). The mean procedure time was comparable: 54.5 ± 17.1 min for POLARx and 59.4 ± 18.6 min for AF-CB4 (P = 0.0509). No differences were observed in terms of periprocedural complications. There were comparable rates in freedom of AF or atrial tachycardia recurrence after 12 months, beyond a 90-day long blanking period: 78.9% in the POLARx group vs. 77.2% in the AF-CB4 group (P = 0.804). CONCLUSION: The novel POLARx CB showed similar safety, efficacy, and 1-year recurrence-free survival rates compared to the AF-CB4. A higher rate of real-time electrical PV recordings and significantly lower balloon temperatures were observed using the POLARx as compared to AF-CB4.

EASY-WPW: a novel ECG-algorithm for easy and reliable localization of manifest accessory pathways in children and adults.

AIMS: Accessory pathway (AP) ablation is a standard procedure for the treatment of Wolff-Parkinson-White syndrome (WPW). Twelve-lead electrocardiogram (ECG)-based delta wave analysis is essential for predicting ablation sites. Previous algorithms have shown to be complex, time-consuming, and unprecise. We aimed to retrospectively develop and prospectively validate a new, simple ECG-based algorithm considering the patients' heart axis allowing for exact localization of APs in patients undergoing ablation for WPW. METHODS AND RESULTS: Our multicentre study included 211 patients undergoing ablation of a single manifest AP due to WPW between 2013 and 2021. The algorithm was developed retrospectively and validated prospectively by comparing its efficacy to two established ones (Pambrun and Arruda). All patients (32 ± 19 years old, 47% female) underwent successful pathway ablation. Prediction of AP-localization was correct in 197 patients (93%) (sensitivity 92%, specificity 99%, PPV 96%, and NPV 99%). Our algorithm was particularly useful in correctly localizing antero-septal/-lateral (sensitivity and specificity 100%) and posteroseptal (sensitivity 98%, specificity 92%) AP in proximity to the tricuspid valve. The accuracy of EASY-WPW was superior compared to the Pambrun (93% vs. 84%, P = 0.003*) and the Arruda algorithm (94% vs. 75%, P < 0.001*). A subgroup analysis of children (n = 58, 12 ± 4 years old, 55% female) revealed superiority to the Arruda algorithm (P < 0.001*). The reproducibility of our algorithm was excellent (Ï°>0.8; P < 0.001*). CONCLUSION: The novel EASY-WPW algorithm provides reliable and accurate pre-interventional ablation site determination in WPW patients. Only two steps are necessary to locate left-sided AP, and three steps to determine right-sided AP.

Impact of cryoballoon application abortion due to phrenic nerve injury on reconnection rates: a YETI subgroup analysis.

AIMS: Cryoballoon (CB)-based pulmonary vein isolation (PVI) is an effective treatment for atrial fibrillation (AF). The most frequent complication during CB-based PVI is right-sided phrenic nerve injury (PNI) which is leading to premature abortion of the freeze cycle. Here, we analysed reconnection rates after CB-based PVI and PNI in a large-scale population during repeat procedures. METHODS AND RESULTS: In the YETI registry, a total of 17 356 patients underwent CB-based PVI in 33 centres, and 731 (4.2%) patients experienced PNI. A total of 111/731 (15.2%) patients received a repeat procedure for treatment of recurrent AF. In 94/111 (84.7%) patients data on repeat procedures were available. A total of 89/94 (94.7%) index pulmonary veins (PVs) have been isolated during the initial PVI. During repeat procedures, 22 (24.7%) of initially isolated index PVs showed reconnection. The use of a double stop technique did non influence the PV reconnection rate (P = 0.464). The time to PNI was 140.5 ± 45.1 s in patients with persistent PVI and 133.5 ± 53.8 s in patients with reconnection (P = 0.559). No differences were noted between the two populations in terms of CB temperature at the time of PNI (P = 0.362). The only parameter associated with isolation durability was CB temperature after 30 s of freezing. The PV reconnection did not influence the time to AF recurrence. CONCLUSION: In patients with cryoballon application abortion due to PNI, a high rate of persistent PVI rate was found at repeat procedures. Our data may help to identify the optimal dosing protocol in CB-based PVI procedures. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT03645577?term=YETI&cntry=DE&draw=2&rank=1 ClinicalTrials.gov Identifier: NCT03645577.

Pulsed Field Ablation-Based Pulmonary Vein Isolation Using a Simplified Single-Access Single-Catheter Approach　- The Fast and Furious PFA Study.

BACKGROUND: Pulsed field ablation (PFA) is a non-thermal energy source with promising safety and efficacy advantages. We aimed to develop a convenient, safe, effective and fast method of pulmonary vein isolation (PVI) utilizing a penta-spline PFA catheter via a single femoral vein and a venous closure system.Methods and Results: Consecutive patients (n=50; mean age: 63.6±10.7 years, 38% female) presenting with AF (paroxysmal AF: 56%) underwent first-time PVI via PFA. A single ultrasound-guided femoral vein puncture and a single transseptal puncture were used. After PVI using the penta-spline PFA catheter, extra pulse trains were added to the posterior wall for wide antral circumferential ablation. A venous closure system was used and a Donati suture was performed. The pressure bandage was removed after 1 h. A total of 196 PVs were identified and isolated with PFA only. The mean procedural time was 27.4±6.6 min, and the mean dwelling time was 14.4±5.5 min. Time to ambulation was 3.3±3.1 h. No severe complications occurred. During a mean follow-up of 6.5±2.1 months, 41/50 patients (82%) remained in sinus rhythm. CONCLUSIONS: The combination of a single venous puncture, single transseptal puncture approach using PFA and vascular closure device resulted in a 100% rate of acute PVI and an extraordinarily fast procedure and time to ambulation. The rate of periprocedural complications was low.

Mechanisms of late arrhythmia recurrence after initially successful pulmonary vein isolation in patients with atrial fibrillation.

BACKGROUND: Catheter ablation is an effective treatment for atrial fibrillation (AF,) but arrhythmia recurrence occurs in a relevant number of patients. Mechanisms of late occurring arrhythmias after ablation procedures are not fully understood. We analyzed electrophysiological mechanisms of early and late arrhythmia recurrences in patients who underwent radiofrequency-based catheter ablation of AF. METHODS AND RESULTS: Consecutive patients who underwent repeat ablation procedures after initial pulmonary vein isolation (PVI) for symptomatic arrhythmia recurrence were analyzed. A total of 110 consecutive patients who underwent catheter ablation for paroxysmal (79%) or persistent AF (21%) were included. Forty-seven patients suffered from early arrhythmia recurrence (group #1: 3-24 months), 29 patients from mid-term arrhythmia recurrences (group #2: 2-5 years), and 34 patients from late arrhythmia recurrences (group #3: > 5 years). Electrical PV reconnection was found in 98% in group #1, 72% in group #2 and 56% in group #3 (p < .001). Mode of arrhythmia recurrence was organized tachycardia in 25%, 28%, and 65% of patients in groups #1, #2, and #3 (p = .001), respectively. Patients with late arrhythmia recurrence had more pronounced left atrial low voltage as compared to patients with early arrhythmia recurrence based on two published scoring system. CONCLUSION: Electrical PV reconnection was found in the majority of patients with early AF recurrence after PVI. In patients with late arrhythmia recurrences this mechanism may play an inferior role, with many patients presenting without PV reconnection, but with LA structural alterations. Thus, early and late occurring arrhythmia recurrence after catheter ablation may be the same symptom of different diseases.

Has COVID-19 changed the spectrum of arrhythmias and the incidence of sudden cardiac death?

Arrhythmic manifestations of COVID-19 include atrial arrhythmias such as atrial fibrillation or atrial flutter, sinus node dysfunction, atrioventricular conduction abnormalities, ventricular tachyarrhythmias, sudden cardiac arrest, and cardiovascular dysautonomias including the so-called long COVID syndrome. Various pathophysiological mechanisms have been implicated, such as direct viral invasion, hypoxemia, local and systemic inflammation, changes in ion channel physiology, immune activation, and autonomic dysregulation. The development of atrial or ventricular arrhythmias in hospitalized COVID-19 patients has been shown to portend a higher risk of in-hospital death. Management of these arrhythmias should be based on published evidence-based guidelines, with special consideration of the acuity of COVID-19 infection, concomitant use of antimicrobial and anti-inflammatory drugs, and the transient nature of some rhythm disorders. In view of new SARS-CoV­2 variants that may evolve, the development and use of newer antiviral and immunomodulator drugs, and the increasing adoption of vaccination, clinicians must remain vigilant for other arrhythmic manifestations that may occur in association with this novel but potentially deadly disease.

Outcome of a polymer-free drug-coated coronary stent in bifurcation lesions-Pilot registry with serial OCT imaging.

BACKGROUND: Polymer-free and carrier-free drug-coated stents (DCS) represent a novel therapeutic option for the treatment of coronary artery disease. The objective of this pilot registry is to evaluate the safety and efficacy of DCS implantation in bifurcation lesions. METHODS: Overall, 23 consecutive patients with 24 lesions received a Biolimus A9-coated DCS for coronary bifurcation lesions. Patients were examined with quantitative coronary angiography (QCA) and optical coherence tomography (OCT) at 3-6 months of follow-up. RESULTS: A total of 23 patients with 24 bifurcation lesions were included in this study. Nine (33.3%) lesions of eight patients revealed angiographical target lesion failure due to in-stent restenosis (ISR). In total, 19 patients with 20 bifurcation lesions were suitable for OCT analysis. A total of 2936 struts were analyzed and 14 struts (0.47%) were classified as malapposed. The mean luminal area (mm2) was not different in lesions with ISR vs. lesions with no ISR (5.07 ± 2.0 vs. 5.73 ± 1.34, p = 0.39) at follow-up. Lesions with ISR showed higher mean neointimal burden (27.11 ± 10.59 vs. 13.93 ± 9.16%, respectively; p = 0.009). All of the patients who presented with significant ISR required percutaneous re-intervention. CONCLUSIONS: We observed a high rate of DCS ISR in bifurcation lesions, possibly related to increased inflammation and neoatherosclerosis. The small size of the study warrants careful interpretation of our results. Larger trials are necessary to expand knowledge of these findings.

Stand-alone Focal Impulse and Rotor Modulation (FIRM) ablation versus second-generation cryoballoon pulmonary vein isolation for paroxysmal atrial fibrillation.

INTRODUCTION: Focal Impulse and Rotor Modulation (FIRM) guided catheter ablation aiming at stable rotors has been investigated as a treatment option in patients with atrial fibrillation (AF). The objective of this study was to compare the safety and efficacy of FIRM-guided ablation with second-generation cryoballoon pulmonary vein isolation (CB2-PVI) in paroxysmal AF. METHODS: Consecutive patients (n = 22, mean age 60 ± 11 years, 59.1% of males) who were treated with a stand-alone FIRM-guided ablation were included in this retrospective single-center study. Procedural data and arrhythmia-free survival at 12 months were compared with n = 86 consecutive patients (mean age 62 ± 13 years, 62.4% of males) who received de-novo CB2-PVI. RESULTS: Median procedure duration was significantly longer in the FIRM group than in the CB2-PVI group (152 [IQR 120-176] minutes vs. 122 [110-145] minutes; p = .031). One patient (1.2%) in the CB2-PVI group and five patients (22.7%) in the FIRM group had vascular access complications. Atrial tachyarrhythmias recurred in 15 patients in the FIRM group and 11 in the CB2-PVI group. Kaplan-Meier estimation of single-procedure arrhythmia-free survival at 12 months was 25% (95% confidence interval [CI] 6%-44%) in the FIRM group and 87% (95% CI 78%-96%) in the CB2-PVI group (p < .001). Repeat ablations were performed in 14/20 (70.0%) patients in the FIRM group and in 12/85 (14.1%) in the CB2-PVI group (p < .001). CONCLUSION: De novo ablation of AF using FIRM-guided AF ablation results in shorter arrhythmia-free survival after 12 months compared to CB2-PVI and a need for repeat ablation in the majority of patients to achieve stable sinus rhythm.

Repeat catheter ablation in patients with atrial arrhythmia recurrence despite durable pulmonary vein isolation.

INTRODUCTION: Arrhythmia recurrence after pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF) is common and often linked to pulmonary vein reconnection. In patients with arrhythmia recurrences despite durable PVI the optimal ablation approach is unclear. The purpose of the present study was to analyze efficacy of extended ablation maneuvers in these patients and predictors of procedural success. METHODS: Consecutive patients with durable PVI undergoing repeat ablation procedures were prospectively enrolled. Patients underwent substrate modification with creation of linear lesions and/or mechanism-specific atrial tachycardia (AT) ablation. Three dimensional-mapping images were analyzed for the presence of left atrial (LA) low-voltage areas according to published scoring systems. RESULTS: Seventy-four patients were analyzed. Mode of recurrence after durable PVI was AF in 27 patients (36.5%) and AT in 47 patients (63.5%). Linear lesion ablation was performed in 60 patients (81.1%). Twenty-four patients (32.4%) were treated for focal AT mechanisms. Mean follow-up was 565 ± 342 days. Estimated arrhythmia-free survival after 24 months was significantly higher in patients with AT than in patients with AF as mode of recurrence after durable PVI (42.9 ± 8.2% vs. 24.7 ± 8.5%, p = .023) and in patients without compared to patients with marked LA low-voltage areas (40.5 ± 9.2% vs. 22.8 ± 8.5%, p = .041). The mode of recurrence after durable PVI was the only independent predictor of further arrhythmia recurrence after repeat ablation. CONCLUSION: Arrhythmia-free survival following repeat ablation procedures in patients with durable PVI highly depends on mode of arrhythmia recurrence and the presence of LA low-voltage areas.

Impact of a time-to-effect-guided ablation protocol in cryoballoon ablation on the durability of pulmonary vein isolation.

BACKGROUND: Cryoballoon (CB)-based pulmonary vein isolation (PVI) has proven to be as effective as radiofrequency-based ablation. Different ablation protocols took the individual time-to-isolation (TTI) into account aiming at shorter but equally or even more effective freeze cycles. The current study sought to assess the impact of the TTI on PVI durability in patients undergoing a repeat procedure for recurrence of atrial tachyarrhythmia (ATA). METHODS AND RESULTS: In 205 patients with ATA recurrence after previous CB-based PVI, a total of 806 pulmonary veins (PVs) were identified. A total of 126 out of 806 PVs (16%) were previously treated with a TTI-guided ablation (Protocol #1; TTI + 120 s), in 92/806 (11%) PVs TTI was only monitored (m) but fixed freeze cycles were applied (Protocol #2; mTTI) and in 588/806 (73%) a fixed freeze cycle was applied without mTTI. There was no difference in the PV-reconduction rate between the groups (p = .23). The right inferior pulmonary vein (RIPV) showed overall significantly higher reconduction rates compared to the other PVs (RIPV-left inferior PV p < .003, -left superior PV p < .001, -right superior PV p < .013). Twenty-one patients (10%) were demonstrated to have only electrical reconduction of the RIPV, while all other PVs were still electrically isolated. CONCLUSIONS: The TTI-based CB ablation protocol did not show significant differences regarding PV-reconduction rates compared to the other ablation protocols.

Individualized or fixed approach to pulmonary vein isolation utilizing the fourth-generation cryoballoon in patients with paroxysmal atrial fibrillation: the randomized INDI-FREEZE trial.

AIMS: Cryoballoon (CB) based pulmonary vein isolation (PVI) is a widely used technique for treatment of atrial fibrillation (AF); however the ideal energy dosing has not yet been standardized. This was a single-centre randomized clinical trial aiming at assessing the safety, acute efficacy, and clinical outcome of an individualized vs. a fixed CB ablation protocol using the fourth-generation CB (CB4) guided by pulmonary vein (PV) potential recordings and CB temperature. METHODS AND RESULTS: Patients were randomized in a 1:1 fashion to two different dosing protocols: INDI-FREEZE group (individualized protocol): freeze-cycle duration of time to effect plus 90 s or interruption of the freeze-cycle and repositioning CB if a CB temperature of -30°C was not within 40 s. Control group (fixed protocol): freeze-cycle duration of 180 s. No-bonus freeze-cycle was applied in either patient group. The primary endpoint was freedom from atrial tachyarrhythmia at 12 months. Secondary end points included procedural parameters and complications. A total of 100 patients with paroxysmal AF were prospectively enrolled. No difference was seen in the primary endpoint [INDI-FREEZE group: 38/47 (81%) vs. control group: 40/47, (85%), P = 0.583]. The total freezing time was significantly shorter in the INDI-FREEZE group (157 ± 56 s vs. 212 ± 83 s, P < 0.001), while procedure duration (57.9 ± 17.9 min vs. 63.2 ± 20.2 min, P = 0.172) was similar. No differences were seen in the minimum CB and oesophageal temperatures as well as in periprocedural complications. CONCLUSION: Compared to the fixed protocol, the individualized approach provides a similar safety profile and clinical outcome, while reducing the total freezing time.

Novel cryoballoon ablation system for pulmonary vein isolation: multicenter assessment of efficacy and safety-ANTARCTICA study.

AIMS: Pulmonary vein isolation (PVI) either by balloon devices or radiofrequency forms the cornerstone of invasive atrial fibrillation (AF) treatment. Although equally effective cryoballoon (CB)-based PVI offers shorter procedure duration and a better safety profile. Beside the worldwide established Arctic Front Advance system, a novel CB device, POLARx, was recently introduced. This CB incorporates unique features, which may translate into improved efficacy and safety. However, multicentre assessment of periprocedural efficacy and safety is lacking up to date. METHODS AND RESULTS: A total of 317 patients with paroxysmal or persistent AF were included and underwent POLARx CB-based PVI in 6 centres from Germany and Italy. Acute efficacy and safety were assessed in this prospective multicenter observational study. In 317 patients [mean age: 64 ± 12 years, 209 of 317 (66%) paroxysmal AF], a total of 1256 pulmonary veins (PVs) were identified and 1252 (99,7%) PVs were successfully isolated utilizing mainly the short tip POLARx CB (82%). The mean minimal CB temperature was -57.9 ± 7°C. Real-time PVI was registered in 72% of PVs. The rate of serious adverse events was 6.0% which was significantly reduced after a learning curve of 25 cases (9.3% vs. 3.0%, P = 0.018). The rate of recurrence-free survival after mean follow-up of 226 ± 115 days including a 90-day blanking period was 86.1%. CONCLUSION: In this large multicentre assessment, the novel POLARx CB shows a promising efficacy and safety profile after a short learning curve.

Acute and long-term success of left atrial anterior line and mitral isthmus line ablation in patients after mitral valve surgery.

BACKGROUND: Perimitral flutter and atrial fibrillation may occur in patients with prior surgical mitral valve (MV) repair or replacement and can be challenging for percutaneous catheter ablation. This study sought to determine the feasibility, acute success and durability of catheter ablation of atrial fibrillation or atrial tachycardia by way of a mitral isthmus line (MIL) or an anterior line (AL). METHODS: A total of 81 patients (49 males, mean age 62±11 years) with prior MV replacement (n = 30) or reconstruction (n = 51) underwent creation of a MIL (34) and/or an AL (72). RESULTS: Acute bidirectional block of the MIL was successfully achieved in 24/34 cases and of the AL in 64/72 patients. Patients of the control group without prior MV surgery were matched 1:1 with the valve group. In the AL control subgroup, acute bidirectional block was achieved in 65/72 patients. Acute blockage in the MIL control subgroup could be achieved in 31/34 patients. The MIL valve subgroup showed the worst results in terms of durability, whereas a similar trend emerged in the control group and the AL valve subgroup (probability of failure in MIL valve subgroup 2.224 vs. MIL control subgroup 0.605 [Hazard Ratio (HR) = 0.27, 95% confidence interval (CI), 0.11-0.65), P = .004]; probability of failure in AL valve subgroup 0.844 vs. AL control subgroup 1.03 [HR = 1.22 (95% CI, 0.66-2.26), P = .523]). CONCLUSIONS: Percutaneous creation of MIL and AL is feasible and safe in patients with prior MV replacement/repair and associated with moderate acute and long-term success rates to achieve bidirectional block.

Preventive or Deferred Ablation of Ventricular Tachycardia in Patients With Ischemic Cardiomyopathy and Implantable Defibrillator (BERLIN VT): A Multicenter Randomized Trial.

BACKGROUND: Catheter ablation for ventricular tachycardia (VT) reduces the recurrence of VT in patients with implantable cardioverter-defibrillators (ICDs). The appropriate timing of VT ablation and its effects on mortality and heart failure progression remain a matter of debate. In patients with life-threatening arrhythmias necessitating ICD implantation, we compared outcomes of preventive VT ablation (undertaken before ICD implantation to prevent ICD shocks for VT) and deferred ablation after 3 ICD shocks for VT. METHODS: The BERLIN VT study (Preventive Ablation of Ventricular Tachycardia in Patients With Myocardial Infarction) was a prospective, open, parallel, randomized trial performed at 26 centers. Patients with stable ischemic cardiomyopathy, a left ventricular ejection fraction between 30% and 50%, and documented VT were randomly assigned 1:1 to a preventive or deferred ablation strategy. The primary outcome was a composite of all-cause death and unplanned hospitalization for either symptomatic ventricular arrhythmia or worsening heart failure. Secondary outcomes included sustained ventricular tachyarrhythmia and appropriate ICD therapy. We hypothesized that preventive ablation strategy would be superior to deferred ablation strategy in the intention-to-treat population. RESULTS: During a mean follow-up of 396±284 days, the primary end point occurred in 25 (32.9%) of 76 patients in the preventive ablation group and 23 (27.7%) of 83 patients in the deferred ablation group (hazard ratio, 1.09 [95% CI, 0.62-1.92]; P=0.77). On the basis of prespecified criteria for interim analyses, the study was terminated early for futility. In the preventive versus deferred ablation group, 6 versus 2 patients died (7.9% versus 2.4%; P=0.18), 8 versus 2 patients were admitted for worsening heart failure (10.4% versus 2.3%; P=0.062), and 15 versus 21 patients were hospitalized for symptomatic ventricular arrhythmia (19.5% versus 25.3%; P=0.27). Among secondary outcomes, the proportions of patients with sustained ventricular tachyarrhythmia (39.7% versus 48.2%; P=0.050) and appropriate ICD therapy (34.2% versus 47.0%; P=0.020) were numerically reduced in the preventive ablation group. CONCLUSIONS: Preventive VT ablation before ICD implantation did not reduce mortality or hospitalization for arrhythmia or worsening heart failure during 1 year of follow-up compared with the deferred ablation strategy. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02501005.