Pulsed field ablation compared to thermal ablation techniques in atrial fibrillation: a German-wide in-hospital safety analysis

In recent years, pulsed field ablation (PFA) has emerged as a promising alternative to established thermal ablation—cryoballoon (CB) and radiofrequency (RF) ablation—for the treatment of atrial fibrillation (AF).1–4 Pulsed field ablation is considered to be more tissue-selective, potentially minimizing collateral damage and complications. The randomized ADVENT trial demonstrated that PFA is non-inferior to conventional ablation regarding AF recurrence and serious adverse events (SAEs).5 Comparable efficacy was also observed in a head-to-head comparison of PFA and CB ablation.6 However, data on in-hospital complications remain inconsistent. A recent survey comprising over 17 000 PFA procedures reported very low rates of SAEs and suggested a reduced risk of collateral injury; however, this study did not include a direct comparison with thermal techniques.7 Given the overall low incidence of SAEs in AF ablation, large-scale comparative studies are needed to draw robust conclusions regarding the safety profiles of the different modalities.8 Therefore, this nationwide analysis of all AF ablations performed in Germany in 2023 compares procedure volumes, patient characteristics, and in-hospital complication rates between PFA and established thermal ablation techniques. Data were obtained from the nationwide German Diagnosis Related Groups (DRG) database, provided by the Research Data Center of the Federal Bureau of Statistics (DESTATIS). It provides aggregated data outcomes rather than individual patient records, eliminating the need for ethics committee approval and informed consent. All patients hospitalized in 2023 with paroxysmal or persistent AF who underwent left atrial catheter ablation were identified using the ICD-10-GM classification systems and established German Operation and Classification System (OPS) codes. Patients with additional atrial flutter were excluded. Details regarding diagnostic criteria, outcome definitions, and patient selection for this study have been previously described by our group.8 For PFA, the codes 8-835.k3 and 8-835.k5 were additionally included. The primary outcome was a composite of SAEs, including mortality, stroke, intracerebral haemorrhage, or pericardiocentesis. Secondary outcomes comprised the individual components of the primary outcome, mechanical ventilation > 48 h, serious bleeding (defined as transfusion of >5 units of red blood cells), vascular complications requiring intervention, acute kidney injury, and length of hospital stay. Statistical analysis included descriptive statistics presented as n (%) or mean ± standard deviation. Group comparisons were performed using χ2 and t-tests as appropriate. To adjust for baseline differences among ablation modalities, inverse probability weighting incorporating previously reported baseline characteristics (Table 1) was applied as described before.8 Statistical significance was set at P < 0.05. Analyses were conducted using Stata 18 (StataCorp, USA) and GraphPad Prism 8 (San Diego, USA). Baseline and outcome characteristics of patients with paroxysmal or persistent AF undergoing pulmonary vein isolation in Germany in 2023, stratified by ablation modality (CB, RF, PF) Data are presented as mean (± standard deviation) or number of patients (percentage). Serious adverse events include in-hospital mortality, stroke, intracerebral bleeding, or pericardiocentesis. P-values are from χ² tests for categorical variables and t-tests for continuous variables. For case numbers of 1–2, exact counts are not reported due to data protection regulations. Statistically significant P-values are shown in bold. ACVB, aortocoronary bypass; AF, atrial fibrillation; CB, cryoballoon; CCI, Charlson Comorbidity Index; COPD, chronic obstructive pulmonary disease; NYHA, New York Heart Association Functional Classification; PFA, pulsed field ablation; RF, radiofrequency. Baseline and outcome characteristics of patients with paroxysmal or persistent AF undergoing pulmonary vein isolation in Germany in 2023, stratified by ablation modality (CB, RF, PF) Data are presented as mean (± standard deviation) or number of patients (percentage). Serious adverse events include in-hospital mortality, stroke, intracerebral bleeding, or pericardiocentesis. P-values are from χ² tests for categorical variables and t-tests for continuous variables. For case numbers of 1–2, exact counts are not reported due to data protection regulations. Statistically significant P-values are shown in bold. ACVB, aortocoronary bypass; AF, atrial fibrillation; CB, cryoballoon; CCI, Charlson Comorbidity Index; COPD, chronic obstructive pulmonary disease; NYHA, New York Heart Association Functional Classification; PFA, pulsed field ablation; RF, radiofrequency. In 2023 95 927 patients with paroxysmal or persistent AF underwent left atrial catheter ablation in Germany. Cryoballoon ablation was performed in 30 766 patients, RF in 32 656, and PFA in 2505. Pulsed field ablation was less frequently performed in female patients compared to CB and RF ablation. Patients undergoing PFA had fewer comorbidities than those receiving RF ablation, including lower rates of heart failure [New York Heart Association Functional Classification (NYHA) Class III/IV], arterial hypertension, chronic kidney disease, diabetes, and Charlson Comorbidity Index (CCI). Compared to the CB group, patients treated with PFA had similar rates of heart failure (NYHA III/IV), but lower rates of chronic kidney disease and diabetes, and a lower CCI overall. Full baseline characteristics are provided in Table 1. All groups showed low rates of complications (Table 1). Serious adverse events did not differ significantly between PFA and the thermal ablation modalities. Similarly, no significant differences in secondary safety outcomes were observed. After adjustment for age, sex, comorbidities, and AF type, PFA was not associated with significantly different risks for any safety outcome compared to thermal ablation (Figure 1). Inverse probability weighted analyses, adjusted for baseline characteristics, comparing PFA with CB (upper panel) and with RF ablation (lower panel). CB, cryoballoon; PFA, pulsed field ablation; RF, radiofrequency. In this nationwide analysis of all left atrial ablation procedures for AF in Germany in 2023—the 1st year PFA was coded separately—we evaluated early safety outcomes of PFA compared to RF and CB ablation. To our knowledge, this represents the largest real-world cohort comparing PFA with established thermal techniques. We report three main findings: firstly, PFA shows a safety profile comparable to RF and CB ablation, with low rates of serious in-hospital complications. Secondly, PFA use remains limited, being performed approximately 10 times less frequently than CB and RF ablation. Thirdly, patients undergoing PFA had fewer comorbidities than those receiving thermal ablation. Despite being a novel technique with a distinct energy delivery method, PFA did not show increased rates of SAEs, even after adjusting for baseline differences. This aligns with early clinical trial and registry data.1,2,5–7,9 In-hospital mortality was low across all groups, consistent with prior registry data.5,7,8 Our real-world data add important comparative insight, particularly for PFA. Contrary to expectations, pericardiocentesis rates were not lower with PFA compared to RF. Prior work showed lower tamponade risk with CB vs. RF and similarly low rates in PFA studies such as MANIFEST-17K.5 The slightly higher rate observed here may reflect early real-world experience and centre-specific learning curves. Additionally, the relatively low number of PFA cases may limit detection of rare complications. Our analysis revealed that patients who underwent RF or CB ablation had significantly more comorbidities and higher CCI and CHA2DS2-VASc scores compared to those who received PFA. This likely reflects clinicians’ tendency to choose thermal techniques for more complex or comorbid patients, given the longer-established track record of these methods. This may also explain the shorter hospital stay observed in the PFA group. Whether this reflects patient selection or procedural advantages remains to be determined, but shorter stays could have implications for healthcare resource utilization. The main limitations of this study stem from its reliance on the OPS and ICD-10 coding systems, which are subject to potential over- or underreporting. As the analysis is based solely on in-hospital administrative data, only complications occurring during the index hospitalization are captured. Consequently, SAEs typically reported within 30 days post-procedure—such as stroke or procedure-related mortality—may be underestimated. Moreover, the dataset does not allow for assessment of procedural details, or long-term outcomes as has been described before.8,10 Pulsed field ablation, despite being a newer technology with different energy delivery method, proves to be similarly safe in the short term when compared to RF and CB ablation and can be considered a viable alternative for the treatment of AF, although further studies are needed to assess long-term outcome. This work was supported by the German Heart Foundation/German Foundation of Heart Research. A.M. was funded by the Berta-Ottenstein-Programme for Advanced Clinician Scientists, Faculty of Medicine, University of Freiburg. We acknowledge support by the Open Access Publication Fund of the University of Freiburg. The data underlying this article were provided by the Research Data Centre of the Federal Statistical Office (DESTATIS). Data will be shared on request to the corresponding author with permission of DESTATIS. Aggregated data are included in the article.

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