BACKGROUND: There are sparse high-quality safety and effectiveness data for pulsed field ablation (PFA) of persistent atrial fibrillation (PerAF), in which lesions beyond pulmonary vein isolation (PVI) are often placed. In addition, no large trials have used insertable cardiac monitors for continuous rhythm monitoring after ablation in patients with PerAF or after PFA in any atrial fibrillation population. In Phase 2 of the ADVANTAGE AF study (A Prospective Single Arm Open Label Study of the FARAPULSE Pulsed Field Ablation System in Subjects With Persistent Atrial Fibrillation), patients with PerAF underwent PFA for PVI and posterior wall ablation (PWA) and, in a subcohort, cavotricuspid isthmus ablation for typical atrial flutter. METHODS: Patients with PerAF underwent PVI and posterior wall ablation with the pentaspline PFA catheter and cavotricuspid isthmus with a novel focal-linear PFA catheter after intravenous nitroglycerin prophylaxis. Patients were followed up for 1 year with continuous rhythm monitoring after ablation with insertable cardiac monitors to emulate traditional intermittent monitoring for the primary efficacy end point and to examine atrial arrhythmia (AA) burden and episode duration. RESULTS: This 255-patient cohort (age, 66.7±9.3 years; female, 29%; CHA ₂ DS ₂ -VASc score, 2.4±1.4; body mass index, 30.9±5.3 kg/m ² ; left atrium diameter, 4.3±0.6 cm) underwent PVI plus posterior wall ablation (99.6%/100% acute success); a subpopulation (n=141; 55.3%) also received cavotricuspid isthmus PFA, with 98.6% achieving bidirectional block without complications (ST-segment changes, ventricular fibrillation). Cavotricuspid isthmus ablation took 8±13 minutes, using 18±6 pulsed field applications and 4±2 mg IV nitroglycerin. The total procedure and atrial dwell times were 105±36 and 59±24 minutes, respectively. Mimicking traditional monitoring, freedom from AA was 73.4% with adverse events in 2.4%, both meeting prespecified end-point criteria. Freedom from recurrent atrial flutter was 97.2%. Detailed analysis of the full insertable cardiac monitor data revealed freedom from AA of ≥30 seconds in 52.0%, and no episode exceeded 24 hours in 94.0% of this PerAF cohort. Both an AA burden >0.1% and longest episode duration >1 hour were predictive of increased health care use. One-year procedural effectiveness was 71.6% and 70.0% using the thresholds of ≤0.1% burden and <1 hour duration, respectively. CONCLUSIONS: In Phase 2 of ADVANTAGE AF, the first multicenter PerAF study of PFA with continuous rhythm monitoring: (1) cavotricuspid isthmus ablation with nitroglycerin prophylaxis was safe and effective, (2) PVI plus posterior wall ablation was safe and effective, and (3) an AA burden <0.1% and AA episode <1 hour duration were end points associated with the lowest health care use. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT05443594.

Background: Cryoballoon-based pulmonary vein isolation (PVI) has emerged as an effective treatment for atrial fibrillation. The most frequent complication during cryoballoon-based PVI is phrenic nerve injury (PNI). However, data on PNI are scarce. Methods: The YETI registry is a retrospective, multicenter, and multinational registry evaluating the incidence, characteristics, prognostic factors for PNI recovery and follow-up data of patients with PNI during cryoballoon-based PVI. Experienced electrophysiological centers were invited to participate. All patients with PNI during CB2 or third (CB3) and fourth-generation cryoballoon (CB4)-based PVI were eligible. Results: A total of 17 356 patients underwent cryoballoon-based PVI in 33 centers from 10 countries. A total of 731 (4.2%) patients experienced PNI. The mean time to PNI was 127.7±50.4 seconds, and the mean temperature at the time of PNI was −49±8°C. At the end of the procedure, PNI recovered in 394/731 patients (53.9%). Recovery of PNI at 12 months of follow-up was found in 97.0% of patients (682/703, with 28 patients lost to follow-up). A total of 16/703 (2.3%) reported symptomatic PNI. Only 0.06% of the overall population showed symptomatic and permanent PNI. Prognostic factors improving PNI recovery are immediate stop at PNI by double-stop technique and utilization of a bonus-freeze protocol. Age, cryoballoon temperature at PNI, and compound motor action potential amplitude loss >30% were identified as factors decreasing PNI recovery. Based on these parameters, a score was calculated. The YETI score has a numerical value that will directly represent the probability of a specific patient of recovering from PNI within 12 months. Conclusions: The incidence of PNI during cryoballoon-based PVI was 4.2%. Overall 97% of PNI recovered within 12 months. Symptomatic and permanent PNI is exceedingly rare in patients after cryoballoon-based PVI. The YETI score estimates the prognosis after iatrogenic cryoballoon-derived PNI. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03645577. Graphic A graphic abstract is available for this article.

Aims: Initial clinical studies of pulsed field ablation (PFA) to treat atrial fibrillation (AF) indicated a >90% durability rate of pulmonary vein isolation (PVI). However, these studies were largely conducted in single centres and involved a limited number of operators. We aimed to describe the electrophysiological findings and outcomes in patients undergoing repeat ablation after an initial PF ablation for AF. Methods and results: In the MANIFEST-REDO study, we investigated patients who underwent repeat ablation due to clinical recurrence—AF or atrial tachycardia (AT)—following first-ever PVI with a pentaspline PFA catheter (Farawave, Boston Scientific Inc.). At 22 centres, 427 patients (age 64 ± 11 years; 37% female) were included. Of note, the recurrent arrhythmia leading to the repeat ablation was paroxysmal AF (51%), persistent AF (30%), or AT (19%). At the repeat procedure, the PV reconnection rates were 30% (left superior pulmonary vein), 28% (left inferior pulmonary vein), 33% (right superior pulmonary vein), and 32% (right inferior pulmonary vein). In 45% of patients, all PVs were durably isolated at the beginning of the repeat procedure, with the previous use of any imaging or mapping modality being univariately associated with durable PVI. After a post-redo follow-up period of 284 (90–366) days, the primary effectiveness endpoint (freedom from documented AF/AT lasting ≥30 s after 3-month blanking without class I/III antiarrhythmic drugs or symptoms) was achieved in 65% of patients, with significant differences between groups (PAF 65% vs. PersAF 56% vs. AT 76%; P = 0.04). Persistent AF as recurrent arrhythmia after the initial PFA ablation predicted AT/AF recurrence after repeat ablation [hazard ratio 1.241 (95% confidence interval 1.534–1.005); P = 0.045]. The procedural complication rate was 2.8%. Conclusion: In repeat procedures for AF/AT performed after an index procedure with PFA for AF, PV reconnections are not uncommon. Repeat procedures can be performed safely and with an acceptable subsequent success rate.

Imaging using cardiac computed tomography (CT) or magnetic resonance (MR) imaging has become an important option for anatomic and substrate delineation in complex atrial fibrillation (AF) and ventricular tachycardia (VT) ablation procedures. Computed tomography more common than MR has been used to detect procedure-associated complications such as oesophageal, cerebral, and vascular injury. This clinical consensus statement summarizes the current knowledge of CT and MR to facilitate electrophysiological procedures, the current value of real-time integration of imaging-derived anatomy, and substrate information during the procedure and the current role of CT and MR in diagnosing relevant procedure-related complications. Practical advice on potential advantages of one imaging modality over the other is discussed for patients with implanted cardiac rhythm devices as well as for planning, intraprocedural integration, and post-interventional management in AF and VT ablation patients. Establishing a team of electrophysiologists and cardiac imaging specialists working on specific details of imaging for complex ablation procedures is key. Cardiac magnetic resonance (CMR) can safely be performed in most patients with implanted active cardiac devices. Standard procedures for pre- and post-scanning management of the device and potential CMR-associated device malfunctions need to be in place. In VT patients, imaging—specifically MR—may help to determine scar location and mural distribution in patients with ischaemic and non-ischaemic cardiomyopathy beyond evaluating the underlying structural heart disease. Future directions in imaging may include the ability to register multiple imaging modalities and novel high-resolution modalities, but also refinements of imaging-guided ablation strategies are expected.

Electro-anatomical mapping may be critical to identify atrial fibrillation (AF) subjects who require substrate modification beyond pulmonary vein isolation (PVI). The objective was to determine correlations between pre-ablation mapping characteristics and 12-month outcomes after a single PVI-only catheter ablation of AF. This study enrolled paroxysmal AF (PAF), early persistent AF (PsAF; 7 days–3 months), and non-early PsAF (>3–12 months) subjects undergoing de novo PVI-only radiofrequency catheter ablation. Sinus rhythm (SR) and AF voltage maps were created with the Advisor HD Grid™ Mapping Catheter, Sensor Enabled™ for each subject, and the presence of low-voltage area (LVA) (low-voltage cutoffs: 0.1–1.5 mV) was investigated. Follow-up visits were at 3, 6, and 12 months, with a 24-h Holter monitor at 12 months. A Cox proportional hazards model identified associations between mapping data and 12-month recurrence after a single PVI procedure. The study enrolled 300 subjects (113 PAF, 86 early PsAF, and 101 non-early PsAF) at 18 centres. At 12 months, 75.5% of subjects were free from AF/atrial flutter (AFL)/atrial tachycardia (AT) recurrence. Univariate analysis found that arrhythmia recurrence did not correlate with AF diagnosis, but LVA was significantly correlated. Low-voltage area (28% of the left atrium in SR [hazard ratio (HR): 4.82, 95% confidence interval (CI): 2.08–11.18; P = 0.0003] and >72% in AF (HR: 5.66, 95% CI: 2.34–13.69; P = 0.0001) was associated with a higher risk of AF/AFL/AT recurrence at 12 months. Larger extension of LVA was associated with an increased risk of arrhythmia recurrence. These subjects may benefit from substrate modification beyond PVI.