Toward a Uniform Ablation Protocol for Paroxysmal, Persistent, and Permanent Atrial Fibrillation

Pulsed Field Energy in Atrial Fibrillation Ablation: From Physical Principles to Clinical Applications

Atrial fibrillation, representing the most prevalent sustained cardiac arrhythmia, significantly impacts stroke risk and cardiovascular mortality. Historically managed with antiarrhythmic drugs with limited efficacy, and more recently, catheter ablation, the interventional approach field is still evolving with technological advances. This review highlights pulsed field ablation (PFA), a revolutionary technique gaining prominence in interventional electrophysiology because of its efficacy and safety. PFA employs non-thermal electric fields to create irreversible electroporation, disrupting cell membranes selectively within myocardial tissue, thus preventing the non-selective damage associated with traditional thermal ablation methods like radiofrequency or cryoablation. Clinical studies have consistently shown PFA's ability to achieve pulmonary vein isolation-a cornerstone of AF treatment-rapidly and with minimal complications. Notably, PFA reduces procedure times and has shown a lower incidence of esophageal and phrenic nerve damage, two common concerns with thermal techniques. Emerging from oncological applications, the principles of electroporation provide a unique tissue-selective ablation method that minimizes collateral damage. This review synthesizes findings from foundational animal studies through to recent clinical trials, such as the MANIFEST-PF and ADVENT trials, demonstrating PFA's effectiveness and safety. Future perspectives point towards expanding indications and refinement of techniques that promise to improve AF management outcomes further. PFA represents a paradigm shift in AF ablation, offering a safer, faster, and equally effective alternative to conventional methods. This synthesis of its development and clinical application outlines its potential to become the new standard in AF treatment protocols.

Catheter ablation for atrial fibrillation in patients with persistent left superior vena cava: Case series and systematic review

Introduction

Persistent left superior vena cava (PLSVC) is the most common form of thoracic venous abnormality. Catheter ablation (CA) for atrial fibrillation (AF) can be complicated by the existence of PLSVC, which could act as an important arrhythmogenic mechanism in AF.

Methods and results

We reported a case series of patients with PLSVC who underwent CA for AF at our center between 2018 and 2021. A systematic search was also performed on PubMed, EMBASE, and Web of Science for research reporting CA for AF in patients with PLSVC. Sixteen patients with PLSVC were identified at our center. Ablation targeting PLSVC was performed in 5 patients in the index procedures and in four patients receiving redo procedures. One patient experienced acute procedure failure. After a median follow-up period of 15 months, only 6 (37.5%) patients remained free from AF/atrial tachycardia (AT) after a single procedure. In the systematic review, 11 studies with 167 patients were identified. Based on the included studies, the estimated prevalence of PLSVC in patients undergoing CA for AF was 0.7%. Ablation targeting PLSVC was performed in 121 (74.7%) patients. Major complications in patients with PLSVC receiving AF ablation procedure included four cases of cardiac tamponades (2%), three cases of cardiac effusion (1.5%), one case of ischemic stroke, and three cases of phrenic nerve injury (1.5%) (one left phrenic nerve and two right phrenic nerve). Pooled analysis revealed that after a median follow-up period of 15.6 months (IQR 12.0–74.0 months), the long-term AF/AT-free rate was 70.6% (95% CI 62.8–78.4%, I² = 0.0%) (Central illustration). Different ablation strategies for PLSVC were summarized and discussed in the systematic review.

Conclusion

In patients with PLSVC, recurrence of atrial arrhythmia after CA for AF is relatively common. Ablation aiming for PLSVC isolation is necessitated in most patients. The overall risk of procedural complications was within an acceptable range.

Extra-Pulmonary Vein Triggers at de novo and the Repeat Atrial Fibrillation Catheter Ablation

Background: Extra-pulmonary vein triggers can play a significant role in atrial fibrillation recurrence after catheter ablation. We explored the characteristics of the extra-pulmonary vein (PV) triggers in de novo and repeat atrial fibrillation (AF) catheter ablation (AFCA).

Methods: We included 2,118 patients who underwent a de novo AFCA (women 27.6%, 59.2 ± 10.9 years old, paroxysmal AF 65.9%) and 227 of them conducted repeat procedures. All included patients underwent isoproterenol provocation tests at the end of the procedure, and then we analyzed extra-PV triggers-related factors.

Results: Extra-PV triggers were documented in 11.7% of patients undergoing de novo AFCA (1.22 ± 0.46 foci per patient) and 28.6% undergoing repeat AFCA (1.49 ± 0.73 foci per patient). Older age and higher LA volume index in de novo procedures and women, diabetes, and higher parasympathetic nerve activity (heart rate variability) in repeat-AFCA were independently associated with the existence of extra-PV triggers. The septum (19.9%), coronary sinus (14.7%), and superior vena cava (11.2%) were common extra-PV foci. Among 46 patients who were newly found to have mappable extra-PV triggers upon repeat procedures, 15 (32.6%) matched with the previous focal or empirical extra-PV ablation sites. The rate of AF recurrence was significantly higher in patients with extra-PV triggers than in those without after de novo (HR 1.91, 95% CI 1.54–2.38, p < 0.001) and repeat procedures (HR 2.68, 95% CI 1.63–4.42, p < 0.001).

Conclusions: Extra-PV triggers were commonly found in AF patients with significant remodeling and previous empirical extra-PV ablation. The existence of extra-PV triggers was independently associated with poorer rhythm outcomes after the de novo and repeat AFCA.