BACKGROUND:Antitachycardia pacing (ATP) can prevent defibrillator shocks and associated adverse outcomes. Opportunities to enhance ATP performance exist, particularly for rapid monomorphic ventricular tachycardia (MVT). Intrinsic ATP (iATP) is the first closed-loop algorithm that designs and auto-adjusts ATP therapy in real time. OBJECTIVE:This study aimed to evaluate iATP performance in a large, real-world cohort. METHODS:This global, prospective, observational study enrolled patients with an iATP-enabled implantable cardioverter-defibrillator or cardiac resynchronization therapy-defibrillator device. The primary objective, to demonstrate iATP could effectively terminate >60% of MVT episodes in the fast ventricular tachycardia (VT) zone, was analyzed using the generalized estimating equations (GEE) method. Additional analyses included overall effectiveness and the rate of MVT acceleration resulting in shock. A post hoc analysis used GEE models to compare iATP data with standard ATP from a retrospective cohort. RESULTS:In total, 1875 enrolled patients were followed for a total of 3200 patient-years, yielding 2575 iATP-treated MVT episodes. Of 265 iATP-treated episodes in the fast VT zone (73 patients), the GEE-estimated success rate was 89.7% (95% confidence interval [CI] 83.6-93.7), exceeding the primary objective. The GEE-estimated rate of iATP-associated MVT acceleration resulting in shock was 2.3%. Compared with standard ATP, iATP almost doubled the odds of VT termination (adjusted odds ratio 1.87; 95% CI 1.32-2.66; P = .0005) and halved the odds of acceleration resulting in shock (adjusted odds ratio 0.43; 95% CI 0.25-0.74; P = .0026). CONCLUSION:In routine practice, iATP was highly effective and safe across all VT rates. Although exploratory, iATP had overall superior termination rates and a lower chance of acceleration resulting in shock than standard ATP.
Abstract Background Hemolysis is a well-recognized consequence of microseconds pulsed field ablation (PFA), however its occurrence with nanoseconds PFA have not been determined. Purpose the aim of the study is to compare hemolysis profiles across different PFA systems. Methods Consecutively patients with AF undergoing first-time PFA ablation with nanosecond, pentaspline, and lattice-tip catheters were included in this prospective analysis. Hemolysis was assessed by haptoglobin (Hp), lactate dehydrogenase, and bilirubin measured before (T1) and after (T2) ablation. Hemolysis was defined as a >10 mg/dL decrease in Hp between T1 and T2. Significant hemolysis was defined as Hp ≤25 mg/dL. Results 94 (63% male, mean age 58.9 ± 1.73) patients were included. No significant baseline and procedural caractheristic was found between the 3 system. The catheters used were nanoseconds, pentaspline and lattice-tip in 30 (32%), 34 (36%) and 34 (32%) respectively. Hemolysis occurred in 88 (91.5%) of patients. Significant hemolysis was observed in 21 (70%) nanosecond, 27 (79.4%) pentaspline and 7 (23%) lattice-tip cases (p<0.001). Univariable and multivariable analysis showed that nanoseconds and pentaspline catheters were associated with a similarly high risk of significant hemolysis compared with lattice-tip catheter (p<0.001). No significant difference was observed between nanoseconds and pentaspline catheter. Hp decrease per application was greater with nanoseconds (1.93 ± 2.87 mg/dL, p = 0.52) and pentaspline (0.73 ± 0.43 mg/dL, p = 0.11) than with lattice-tip (0.04 ± 0.05 mg/dL, p = 0.43). catheter. Conclusions Hemolysis commonly occurs across PFA procedures, irrespective of pulse duration, and is greater with single-shot than focal system.
Abstract Introduction Pulsed-field ablation (PFA), is a non-thermal energy source widely used in interventional cardiac electrophysiology. Although electroporation is highly selective for myocardial tissue, it is not known which ablation parameters allow for the creation of effective and long-lasting lesions during PFA. Purpose In this study, we sought to evaluate which PFA settings are associated with chronic effective atrial lesions in swine undergoing PFA with the OMNYPULSE ablation catheter. Methods Twelve pigs were equally sorted into 2 groups according to the PFA dose: x6 (group A) vs. x12 applications per ablation (Group B). Three-dimensional mapping of the atria (CARTO) was followed by PFA at the right superior (RSPV) and right inferior pulmonary veins (RIPV), cavotricuspid isthmus (CTI), right atrial prosterior wall (RAPW), left atrial (LA) roof, and mitral annulus (MA). Chronic lesion transmurality and contiguity were assessed on 30-day histology. Transmurality was defined as >80% fibrotic replacement of the whole myocardial thickness post ablation in at least one histology sample. Lesion contiguity was defined as the absence of gaps for more than 75% of the lesion length at any site. Results The procedure proved to be safe and effective. No periprocedural complications occurred in either of the two groups analyzed. Contact force values displayed no differences between the two groups (Group A: 29 ± 15 g vs. Group B: 29 ± 15 g). At 30-day histological evaluation, transmural and contiguous lesions were observed at the RPVs (100%) regardless of the electroporation dose used. In contrast, non-transmural lesions were observed at the MA (16.7–20%) and LA roof (0–20%) despite the presence of deep lesions in these anatomical regions. Finally, the PFA dose was found to be decisive in obtaining deep, contiguous, and transmural lesions at the other sites investigated, namely the CTI (Group A: 83% and Group B: 100%) and the RAPW (Group A: 83% and Group B: 100%). Conclusions PFA ablation with OMNYPULSE proved feasible, however, different atrial sites require specific PFA settings to achieve lesion transmurality and contiguity. Further studies are required to identify the optimal PFA parameters to achieve effective lesions in this setting.
Abstract Background Previous report on acute isolation of extrapulmonary area with pulse field ablation (PFA) showed good acute results but long-term outcomes are still variable. Aim The aim of our study was to analyse the difference between a single shot pentaspline PFA and a focal lattice-tip dual energy catheter. Methods We analysed prospectively collected data of consecutive non-paroxysmal AF patients undergoing redo ablation procedure underwent isolation of left atrial appendage (LAA) and coronary sinus (CS) and ablation of mitral isthmus (MI) between November 2024 and September 2025. CS isolation was performed endocardially with the catheter on the floor of the left atrium and epicardially inside the CS. LAA isolation was performed with application at the ostium and inside the LAA. MI was ablated from the left inferior pulmonary vein to the mitral valve in a linear fashion. Results 297 patients (161, 54.2% male) undergoing repeat-ablation were included in our analysis. 78 patients (26.3%) underwent ablation with the lattice-tip catheter using PFA only, 104 patients (35.0%) with the lattice-tip catheter using a combination of PFA and radiofrequency at the LAA ostium, and 115 patients (38.7%) with the pentaspline catheter. Acute isolation and block were achieved in all patients. At remapping at 98±24days during LAA occlusion, persistent isolation of LAA was found in 5(6.4%), 69(63.5%) and 1(0.9%) patients with lattice-tip PFA only group, lattice-tip using energy combination and pentaspline respectively; MI block was observed in 95 (52.2%) and 2(1.7%) with lattice-tip and pentaspline; CS isolation in 83(45%) and 2(1.7%) with lattice-tip and pentaspline. Conclusion Dual-energy catheter showed significantly a higher incidence of persistent isolation in extra-pulmonary area when compared to single-shot PFA catheter.
Abstract Background Pulmonary vein isolation (PVI) alone is often insufficient for catheter ablation (CA) of persistent atrial fibrillation (PerAF), and the benefit of additional left atrial posterior wall ablation (LAPWA) remains controversial. Purpose We investigated whether signals recorded with a pentaspline pulsed field ablation (PFA) catheter can identify PerAF patients with rapid LAPW activity who may benefit from LAPWA. Additionally, we evaluated whether PFA-induced atrial fibrillation cycle length (AF-CL) prolongation, measured from the coronary sinus (CS), predicts arrhythmia-free survival. Methods In this multicenter observational study, consecutive PerAF patients undergoing first-time ablation with a pentaspline PFA catheter were included. PVI and LAPWA were performed in all cases. AF-CL was measured using the FARS-10 method at three time points: baseline, post-PVI, and post-LAPWA, using distal CS signals. LAPW-CL was measured post-PVI from multiple LAPW positions, with the fastest value retained. Arrhythmic recurrence was defined as any atrial tachyarrhythmia (ATA) lasting >30 seconds beyond the 2-month blanking period. Results Among 270 included patients (mean age 67.1 ± 11.0 years; 29.6% female). Median AF duration was 12 [9-20] months. The overall 12-month ATA-free survival was 72.6%. "Fast LAPW activity" was defined as a LAPW-CL value shorter than the mean LAPW-CL of the entire cohort (191.4±2.4 msec; ≤ 190 msec). Fast LAPW activity was not associated with arrhythmia recurrence (OR 1.263, 95% CI: 0.739–2.160; p=0.393). In contrast, a greater CS-CL prolongation following PVI + LAPWA was independently associated with lower recurrence risk (OR for arrhythmia recurrence 0.298, 95% CI: 0.017–0.520; p<0.001). A CS-CL increase >23.5% from baseline had a sensitivity of 0.65 and specificity of 0.72 for predicting ATA-free survival. Conclusion Post-PVI fast LAPW activity does not predict recurrence after LAPWA in PerAF patients. However, a CS-CL prolongation >23.5% after LAPWA may serve as a useful real-time marker of effective substrate modification and arrhythmia control
