Aims: Pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) in patients with paroxysmal atrial fibrillation (PAF) is effective but hampered by pulmonary vein reconnection due to insufficient ablation lesions. High-power delivery over a short period of time (HPSD) in RFA is stated to create more efficient lesions. The aim of this study was to compare intraprocedural safety and outcome of HPSD ablation to conventional power settings in patients undergoing PVI for PAF. Methods and results: We included 197 patients with PAF that were scheduled for PVI. An ablation protocol with 70 W and a duration cut-off of 7 s at the anterior left atrium (LA) and 5 s at the posterior LA (HPSD group; n = 97) was compared to a conventional power protocol with 30–40 W for 20–40 s (standard group; n = 100) in terms of periprocedural complications and a 1-year outcome. The HPSD group showed significantly less arrhythmia recurrence during 1-year follow-up with 83.1% of patients free from atrial fibrillation compared to 65.1% in the standard group (P < 0.013). No pericardial tamponade, periprocedural thromboembolic complications, or atrio-oesophageal fistula occurred in either group. Mean radiofrequency time (12.4 ± 3.4 min vs. 35.6 ± 12.1 min) and procedural time (89.5 ± 23.9 min vs. 111.15 ± 27.9 min) were significantly shorter in the HPSD group compared to the standard group (both P < 0.001). Conclusion: High-power short-duration ablation demonstrated a comparable safety profile to conventional ablation. High-power short-duration ablation using 70 W for 5–7 s leads to significantly less arrhythmia recurrences after 1 year. Radiofrequency and procedural time were significantly shortened.

BACKGROUND: Pulsed field ablation (PFA) is increasingly used in clinical practice for the treatment of atrial fibrillation. While the susceptibility of erythrocytes to electroporation is well established, the effect of cardiac PFA technologies on hemolysis has remained underreported. The aim of this study was to investigate the incidence, severity, and clinical impact of PFA-induced hemolysis. METHODS: We included n=145 patients undergoing atrial fibrillation catheter ablation with a pentaspline PFA catheter (biphasic, bipolar pulses of 2 kV) and n=70 patients receiving radiofrequency ablation (40–90 W) at 4 high-volume European centers. The lesion set comprised pulmonary vein isolation for paroxysmal atrial fibrillation and pulmonary vein isolation±additional lesions for persistent atrial fibrillation. Hemolysis and renal function biomarkers were analyzed in blood samples at baseline, at the end of ablation, and 24 hours after the procedure. RESULTS: Baseline characteristics were well balanced between groups (overall mean 65.7±9.4 years; 69.3% men). The ablation procedures comprised a mean of 61.6±27.4 PFA deliveries and 26.3±15.0 minutes RF duration. Hemolysis was detected in 94.3% versus 6.8% of patients after PFA versus radiofrequency ablation ( P <0.001): PFA was associated with significantly lower haptoglobin levels (0.5±0.4 versus 1.0±0.4 g/L), while free plasma hemoglobin (592.8±330.6 versus 147.8±183.0 mg/L), bilirubin (21.3±11.3 versus 14.8±8.8 µmol/L), and LDH (lactate dehydrogenase, 352.7±115.7 versus 253.2±56.5 U/L) were significantly higher after PFA compared with radiofrequency ablation (all P <0.001). Hemolysis correlated with the number of PFA deliveries (r=0.62 [95% CI, 0.33–0.80]; P <0.001), with the highest severity occurring ≥54 PFA deliveries. After PFA, hemoglobinuria occurred in 36.4%, while creatinine increase was higher in patients with baseline glomerular filtration rate 50 mL/min (Δcrea, 27.0±103.1 versus −0.2±12.1 µmol/L; P =0.010). CONCLUSIONS: Intravascular hemolysis is a frequent finding after PFA and increases with the number of PFA deliveries. Until the clinical impact of PFA-associated hemolysis is fully elucidated, a careful titration of PFA deliveries during the ablation procedure is warranted.

Introduction: Pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) is an established treatment strategy for atrial fibrillation (AF). To improve PVI efficacy and safety, high‐power short‐duration (HPSD) ablation and pulsed‐field ablation (PFA) were recently introduced into clinical practice. This study aimed to determine the extent of myocardial injury and systemic inflammation following PFA, HPSD, and standard RFA using established biomarkers.Methods: We included 179 patients with paroxysmal AF receiving first‐time PVI with different ablation technologies: standard RFA (30–40 W/20–30 s, n = 52), power‐controlled HPSD (70 W/5–7 s, n = 60), temperature‐controlled HPSD (90 W/4 s, n = 32), and PFA (biphasic, bipolar waveform, n = 35). High‐sensitivity cardiac troponin T (hs‐cTnT), creatine kinase (CK), CK MB isoform (CK‐MB), and white blood cell (WBC) count were determined before and after ablation.Results: Baseline characteristics were well‐balanced between groups (age 63.1 ± 10.3 years, 61.5% male). Postablation hs‐cTnT release was significantly higher with PFA (1469.3 ± 495.0 ng/L), HPSD‐70W (1322.3 ± 510.6 ng/L), and HPSD‐90W (1441.2 ± 409.9 ng/L) than with standard RFA (1045.9 ± 369.7 ng/L; p < .001). CK and CK‐MB release was increased with PFA by 3.4‐fold and 5.8‐fold, respectively, as compared to standard RFA (p < .001). PFA was associated with the lowest elevation in WBC (Δ1.5 ± 1.5 × 10⁹/L), as compared to standard RFA (Δ3.8 ± 2.5 × 10⁹/L, p < .001), HPSD‐70W (Δ2.7 ± 1.7 × 10⁹/L, p = .037), and HPSD‐90W (Δ3.6 ± 2.5 × 10⁹/L, p < .001).Conclusion: Among the four investigated ablation technologies, PFA was associated with the highest myocardial injury and the lowest inflammatory reaction.

Significance: In this study we have identified a mechanism that links pathophysiological ADAMTS13 deficiency to innate immunity and hemostasis by facilitating monocyte extravasation as a prerequisite for their subsequent on-site differentiation into proinflammatory macrophages under conditions of both physiological laminar flow and disturbed reduced flow, e.g., as occurs at atherosclerosis predilection sites. Our bioassay approach using patients’ plasma may become a useful diagnostic tool to assess ADAMTS13 activity ex vivo under conditions of near-physiological to atherosclerosis-prone arterial blood flow, which seems to be more relevant than the conventional static FRET-based assay method.

Background: Early recurrence of atrial tachyarrhythmia (ERAT) is common after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF), but its clinical significance in patients with persistent AF remains unclear. We sought to determine the predictive value of ERAT for rhythm outcome after RFCA for persistent AF. Methods: The study included 207 consecutive patients (mean age 66.4 ± 10.7 years, male 66.2%) with persistent and long-standing persistent AF undergoing de novo pulmonary vein isolation (± atrial substrate ablation). All patients remained off antiarrhythmic drugs. ERAT was defined as any atrial arrhythmia ≥ 30 s occurring within the first 30 days. Late recurrence (LR) was determined during follow-up visits scheduled 1, 3, 6 and 12 months post-ablation using 7-day Holter ECGs. Results: ERAT occurred in 143/207 (69.1%) patients as AF (60%) or atrial tachycardia (40%) and was persistent in 82% of cases. During a median follow-up of 22.2 months, LR occurred significantly more often in patients with ERAT than in patients without ERAT (92.3 vs. 43.8%, P < 0.001). The only independent predictors for LR were ERAT (OR 16.8, 95% CI 6.184–45.797, P < 0.001) and intraprocedural termination to sinus rhythm (OR 0.052, 95% CI 0.003–0.851, P = 0.038). Extending the blanking period from 30 to 90 days did not impact LR rates. Conclusion: ERAT following ablation of persistent AF is strongly associated with late arrhythmia recurrence, which challenges the assumption that ERAT represents merely a transient phenomenon. While limiting the blanking period to 30 days seems justified, the benefit of early re-ablations remains to be addressed in future studies. Graphic

This retrospective study sought to compare complication rates and efficacy of power-controlled very high-power short-duration (vHPSD) and conventional catheter ablation in a large cohort of patients with atrial fibrillation (AF). We analyzed 1115 consecutive patients with AF (38.7% paroxysmal, 61.3% persistent) who received first-time catheter ablation at our centre from 2015 to 2021. Circumferential pulmonary vein isolation ± additional substrate ablation using an irrigated-tip catheter was performed with vHPSD (70 W/5–7 s or 60 W/7–10 s) in 574 patients and with conventional power (30–35 W/15–30 s) in 541 patients. Baseline characteristics were well-balanced between groups (mean age 65.1 ± 11.2 years, 63.4% male). The 30-day incidence of cardiac tamponade [2/574 (0.35%) vs. 1/541 (0.18%), P = 0.598], pericardial effusion ≥ 10 mm [2/574 (0.35%) vs. 1/541 (0.18%), P = 0.598] and transient ischaemic attack [1/574 (0.17%) vs. 2/541 (0.37%), P = 0.529] was not significantly different between vHPSD and conventional ablation. No stroke, atrio-esophageal fistula, cardiac arrest or death occurred. Procedure (122.2 ± 46.8 min vs. 155.0 ± 50.5 min, P < 0.001), radiofrequency (22.4 ± 19.3 min vs. 52.9 ± 22.0 min, P < 0.001), and fluoroscopy (8.1 ± 7.2 vs. 9.2 ± 7.4, P = 0.016) duration were significantly shorter in the vHPSD group. At 12 months follow-up, freedom of any atrial arrhythmia was 44.1% vs. 34.2% (P = 0.010) in persistent AF and 78.1% vs. 70.2% in paroxysmal AF (P = 0.068). vHPSD ablation is as safe as conventional ablation and is associated with an improved long-term efficacy in persistent AF.