Ante Anic

Aims: Pulsed field ablation (PFA) has emerged as a transformative approach for treating cardiac arrhythmias by exploiting irreversible electroporation to preferentially injure myocardium while limiting collateral damage. Translating this biophysical principle into safe and effective clinical systems requires careful integration of waveform design, catheter engineering, computational and experimental modelling, safety testing, and procedural workflow. Objective: This review summarizes the fundamental physical and engineering principles that govern cardiac PFA and examines how these principles influence efficacy, safety, lesion formation, and clinical usability. Biophysical and technical considerations: Electroporation is governed primarily by the local electric field and waveform-dependent lethal thresholds rather than generator voltage alone. Key waveform variables include monophasic vs. biphasic pulses, microsecond vs. nanosecond pulse widths, duty cycle, and total application duration. Catheter design further determines electric field distribution, lesion geometry, current density, and applicability across anatomic targets, with important distinctions between bipolar and monopolar configurations. Modelling and safety: Experimental and computational approaches used to investigate PFA include finite element simulations, cell culture systems, vegetal substrates, and in vivo animal models, each with distinct strengths and limitations. High-voltage pulse delivery can also produce unintended effects, including Joule heating, electrochemical reactions, bubble formation, arcing, and interactions with implanted electronic devices. These phenomena highlight the importance of optimized waveform design, electrode configuration, and safety monitoring. Clinical usability: Clinical adoption depends not only on biological efficacy and safety but also on workflow efficiency, catheter versatility, procedure duration, mapping integration, anaesthesia requirements, and adaptability to differing clinical practices and geographic settings. Conclusions: The performance of a PFA system reflects the interaction of biophysics, waveform characteristics, catheter design, modelling, safety controls, and procedural usability. Understanding these interconnected principles is essential for developing PFA technologies that are effective, safe, predictable, and practical for contemporary electrophysiology laboratories.

Pulsed field ablation has emerged as a novel non-thermal treatment modality with a distinct safety profile for the interventional treatment of atrial fibrillation. By inducing irreversible electroporation, pulsed field ablation achieves myocardial ablation while preserving surrounding structures such as nerves, vasculature, and the oesophagus. This European Heart Rhythm Association of the European Society of Cardiology scientific statement, endorsed by major international societies, reviews the biophysics, technology, clinical evidence, workflow, safety, and training aspects of pulsed field ablation. Randomized trials demonstrate comparable efficacy to radiofrequency and cryoballoon ablation, with advantages in safety and efficiency. The statement provides practical advice for clinical implementation and operator training and identifies key gaps in evidence and priorities for future research and innovation.

Background: Thromboembolic events, though infrequent, remain a significant complication of atrial fibrillation (AF) ablation, largely related to endothelial damage. Cryoballoon (CB) and radiofrequency ablation can induce pro-coagulant responses, whereas pulsed-field ablation (PFA), a novel non-thermal electroporation-based technique, has shown tissue selectivity with potential endothelial-sparing effects. Methods: We aimed to compare PFA and second-generation CB ablation regarding endothelial injury in patients with paroxysmal AF. In this single-center prospective observational study, 25 patients with paroxysmal drug-refractory AF underwent pulmonary vein isolation using either a pentaspline PFA catheter (n = 14) or a second-generation CB catheter (n = 11). Circulating von Willebrand factor antigen (vWF) levels were assessed before and after ablation as a biomarker of endothelial damage, alongside routine laboratory and echocardiographic parameters. Procedural characteristics were also analyzed. Results: Baseline demographic, clinical, and echocardiographic data were comparable between groups. PFA was associated with significantly shorter skin-to-skin procedure time (59 vs. 94 min, p = 0.005) and left atrial dwell time (44 vs. 79 min, p < 0.001) compared with CB ablation. Importantly, vWF levels decreased significantly after PFA (−7.6%, p = 0.007), while CB ablation showed a non-significant increase (+9.5%, p = 0.155). The between-group difference in percent change of vWF was statistically significant (−5.6% vs. +8.3%, p = 0.006). Conclusions: PFA was associated with reduced endothelial injury and shorter procedural times compared with CB ablation, suggesting a potential advantage in lowering thromboembolic risk. These findings support the concept of PFA as an “endothelial sparing” ablation modality. However, the PFA procedure was associated with a significantly greater extent of myocardial injury, as reflected in circulating high-sensitivity cardiac troponin T values, compared to CB ablation (p = 0.007). Larger, randomized studies are warranted to confirm these results and evaluate long-term clinical outcomes.

Aims: Atrial fibrillation (AF) ablation is associated with complications. These are sometimes categorized as mild or severe based on unspecified criteria. We conducted a survey of European electrophysiologists (EPs) to rank the perceived complication severity. Methods and results: A physician-based survey was conducted by the Scientific Initiative Committee of the European Heart Rhythm Association (EHRA). An online questionnaire was created asking EPs to score a list of complications on a scale from 0 (no complication) to 100 (procedural death). Three hundred respondents participated in the survey; however, 105 were excluded due to incomplete responses. Unexplained periprocedural death (90, interquartile range 50–100), atrio-oesophageal fistula (AEF 92, 80–100), procedural stroke (80, 59–89), and tamponade requiring surgery (70, 80–83) were the complications associated with highest scores. Among the intermediate complications, phrenic nerve palsy at discharge (49, 25–67) was ranked similarly to tamponade treated with pericardial puncture (50, 25–70) or periprocedural transient ischaemic attack (50, 25–70). Institutional infrastructural features such as cardiac surgery or stroke units had no impact on the scoring. Most respondents (89%) have experienced cardiac tamponade, procedural stroke (53%), and AEF (25%). When applied retrospectively to existing studies, the proposed EHRA AF ablation safety score demonstrated a trend towards improved AF ablation safety over time. Conclusion: The EHRA complication severity score provides a standardized, quantitative ranking of AF ablation complications, identifying periprocedural death and AEF as the most severe events. Based on the findings, we propose a novel EHRA AF ablation safety score that may contribute to a more objective safety comparison of AF ablation trials.

Aims: Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. However, the optimal strategy during repeat ablation is not clear. This European Heart Rhythm Association (EHRA) survey aims to assess real-world ablation strategies in patients undergoing repeat AF ablation. Methods and results: A 25-item questionnaire was distributed among healthcare professionals via EHRA between 22 May and 21 June 2024. Of the 211 respondents from 43 countries, 58.1% of respondents planned a redo after multiple symptomatic recurrences of atrial arrhythmias. Most repeat procedures (68.0%) are performed within 3 months after the decision for re-intervention. 3D mapping and radiofrequency (RF) catheters with contact force (CF) sensing are the most common modality used for repeat ablation. In patients with more than one pulmonary vein (PV) reconnection, most commonly reisolation of the PVs plus individualized substrate-based ablation is performed (62.2%). When empirical ablation is performed, the most common targets include cavotricuspid isthmus (22.5%), posterior wall isolation (20.7%), left atrial roofline (16.1%), anterior line (12.9%), superior vena cava (8.6%), and vein of Marshall (8.6%). In patients without PV reconnection at repeat procedure, substrate mapping/individualized ablation is the preferred strategy (77.9%). No additional right atrial ablation beyond the CTI was reported. The majority of respondents (60.7%) consider rate control after ≥3 failed ablations. Conclusion: Real-world strategies for repeat AF ablation show significant variability. 3D mapping and CF-guided RF ablation are commonly utilized. Re-PVI and substrate-based ablation are the predominant approaches. However, the optimal strategy beyond durable PVI remains to be further evaluated.

Thromboembolic events, though infrequent, remain a significant complication of atrial fibrillation (AF) ablation, largely related to endothelial damage. Cryoballoon (CB) and radiofrequency ablation can induce pro-coagulant responses, whereas pulsed-field ablation (PFA), a novel non-thermal electroporation-based technique, has shown tissue selectivity with potential endothelial-sparing effects. We aimed to compare PFA and second-generation CB ablation regarding endothelial injury in patients with paroxysmal AF. In this single-center prospective observational study, 25 patients with paroxysmal drug-refractory AF underwent pulmonary vein isolation using either a pentaspline PFA catheter (n=14) or a second-generation CB catheter (n=11). Circulating von Willebrand factor antigen (vWF) levels were assessed before and after ablation as a biomarker of endothelial damage, alongside routine laboratory and echocardiographic parameters. Procedural characteristics were also analyzed. Baseline demographic, clinical, and echocardiographic data were comparable between groups. PFA was associated with significantly shorter skin-to-skin procedure time (59 vs. 94 min, p=0.005) and left atrial dwell time (44 vs. 79 min, p<0.001) compared with CB ablation. Importantly, vWF levels decreased significantly after PFA (−7.6%, p=0.007), while CB ablation showed a non-significant increase (+9.5%, p=0.155). The between-group difference in percent change of vWF was statistically significant (−5.6% vs. +8.3%, p=0.006). PFA was associated with reduced endothelial injury and shorter procedural times compared with CB ablation, suggesting a potential advantage in lowering thromboembolic risk. These findings support the concept of PFA as an “endothelial-sparing” ablation modality. Larger, randomized studies are warranted to confirm these results and evaluate long-term clinical outcomes.