BACKGROUND:Pulmonary vein isolation (PVI) using thermal energy-radiofrequency (RF) or cryoablation (CRYO)-is associated with direct myocardial injury and collateral neural damage. In contrast, pulsed electric field (PEF) energy has emerged as a neural-sparing alternative. There is a lack of quantitative data on proportional neural damage resulting from individual ablation energies. OBJECTIVE:To assess the impact of PVI by RF, CRYO and PEF on the release of plasma biomarkers of myocardial and neural damage. METHODS:This study included 85 patients with paroxysmal atrial fibrillation undergoing PVI (age: 61 ± 12 years, 74% males). Ablation was performed with PEF in 32 patients, RF in 23, and CRYO in 30. Peripheral venous blood samples were collected before, immediately after PVI, and the day after the procedure to measure plasma levels of S100 binding protein (S100B), high-sensitivity troponin I (hsTnI), and high-sensitivity troponin T (hsTnT). Groups were compared based on maximum biomarker levels and the (hsTnI/hsTnT)/S100B ratio as an index of cardioselectivity. RESULTS:Following PVI, all energy modalities caused significant myocardial injury, with PEF showing the most pronounced effects (maximum hsTnT: 1476, 958 and 967 ng/L; maximum hsTnI: 12659, 1699 and 8109 ng/L; for PEF, RF and CRYO, respectively). Maximum S100B levels indicating the neural impact were highest in the CRYO group (80, 80 and 190 ng/L for PEF, RF and CRYO, respectively). PEF exhibited the greatest cardioselectivity, as indicated by the highest (hsTnI/hsTnT)/S100B ratio (0.11 ± 0.04, 0.02 ± 0.01 and 0.05 ± 0.05 for PEF, RF and CRYO, respectively). Interestingly, no correlation was observed between S100B release and heart rate acceleration (R = 0.07, p = 0.51). CONCLUSION:PEF is the most cardioselective modality of ablation energy currently available for the treatment of atrial fibrillation. The neuromodulatory effect of PVI on the sinus node appears to be independent of the magnitude of neural damage.

Radiofrequency ablation of the superior paraseptal ganglionated plexus attenuates vagal modulation of the sinus node (SAN). Ablation from the right-atrium aspect can achieve a sufficient effect. In a randomized study, we investigated the ablation effects of an anatomically prespecified right atrial linear lesion. Twenty patients (age 48 ± 13 years, 70

AIMS:Cavotricuspid isthmus (CTI) ablation is commonly performed alongside catheter ablation of atrial fibrillation (AF). However, the acute efficacy of the CTI ablation using the pentaspline catheter and pulsed electric field (PEF) energy has not been systematically evaluated. This randomized study assessed the acute efficacy and extent of haemolysis associated with CTI ablation when performed using two different configurations of the pentaspline catheter. METHODS AND RESULTS:A total of 178 patients (age 65 ± 10 years, 66% of males) undergoing PEF ablation of the CTI in conjunction with AF ablation were randomly assigned to receive ablation using either the basket configuration (n = 95) or the flower configuration (n = 83) of the pentaspline catheter. The CTI ablation was performed before left atrial ablation. It was guided by intracardiac echocardiography, and bidirectional block was confirmed by pacing manoeuvres. Venous blood samples to assess haemolytic biomarkers were collected before and immediately after the CTI ablation. The groups were broadly comparable in baseline characteristics. The flower group demonstrated superior procedural efficiency, with fewer applications required to achieve a CTI block (3.4 ± 3.1 vs. 8.0 ± 4.1, P < 0.001), a shorter time to block (96 ± 289 vs. 177 ± 192 s, P < 0.001), and fewer total applications (10.1 ± 3.4 vs. 13.3 ± 5.1, P < 0.001). Acute reconduction occurred in 20% of cases overall, but was significantly lower in the flower group (6% vs. 32%, P < 0.001; hazard ratio: 0.14, 95% confidence interval: 0.06-0.40). Haemolysis was notably lower in the flower group, with significantly less post-procedural free haemoglobin (154 ± 112 vs. 210 ± 115 mg/L, P < 0.001). One case of transient ST elevations occurred in the flower group without clinical consequence. CONCLUSION:Pulsed electric field ablation of the CTI using the flower configuration of the pentaspline catheter demonstrated higher acute efficacy in achieving CTI block and a more favourable safety profile regarding haemolysis compared to the basket configuration. This is likely due to the larger footprint and improved tissue contact of all electrodes, minimizing the leakage of PEF energy into the blood pool.

Abstract Background Pulmonary vein isolation (PVI) by thermal energy, both radiofrequency (RF) and cryoenergy(Cryo), is associated with a significant release of myocardial and collateral neural injury markers. Damage to periatrial ganglionated plexi also results in a substantial change in cardiac autonomic regulations. On the contrary, pulsed electric field (PEF) energy tends to spare cardiac neural tissue. Purpose To quantify the impact of different ablation energy sources that are used for PVI on neuro-myocardial damage by the assessment of specific biomarkers. Methods A study enrolled 85 patients with paroxysmal atrial fibrillation who underwent PVI (age: 61 ± 12 years, 74% males). In 23 patients, RF energy was delivered by the irrigated-tip catheter, while 30 patients were ablated using a second-generation cryoballoon catheter. In 32 patients, PVI was performed using a multipolar pentaspline catheter and PEF energy. Peripheral venous blood samples for assessing the plasmatic levels of S100 calcium-binding protein B (S100B), neuron-specific enolase (NSE), high-sensitivity troponin I and T (hsTnI and hsTnT) were obtained before, immediately after the PVI, and the next day (usually 18-24 hours after the procedure). Study groups were compared regarding absolute biomarker levels and hsTnT/S100B ratio (a surrogate of cardioselectivity). Results Following successful PVI, a significant increase in plasma levels of all biomarkers was observed: DhsTnT = 1040±434 ng/L, 1731±830 ng/L and 1010±397 ng/L; DhsTnI = 1504±918 ng/L, 16464±11911 ng/L and 10789±7589 ng/L; DS100B: 0.04±0.02 mg/L, 0.03±0.04 mg/L and 0.14±0.08 mg/L; DNSE: 34±72 ng/mL, 27±53 ng/mL and 45±52 ng/mL (all with P <0.001) for RF, PEF and Cryo groups, respectively. A direct comparison of maximal biomarker levels between study groups is depicted in the Figure. The hsTnT/S100B ratio was 23±14, 12±6, and 6±3 in PEF, RF, and Cryo groups, respectively (ANOVA P <0.01), indicating that PEF was 1.9-times and 3.8-times more cardioselective than RF and Cryo, respectively. Following the PVI, the heart rate accelerated by 2±8, 13±14, and 9±11 bpm in the PEF, RF, and Cryo groups, respectively. No correlation was observed between S100B release and HR acceleration (R = 0.07, P = 0.55). Conclusion Compared to thermal energy sources, PEF energy induces more specific damage to cardiomyocytes than cardiac nerves. There was no correlation between S100B release and HR acceleration.

INTRODUCTION:Atrial fibrillation (AF) can cause or aggravate heart failure (HF). Catheter ablation (CA) is an effective treatment for AF. This study focused on the feasibility and outcomes of emergent AF ablation performed during hospitalization for acute HF. METHODS AND RESULTS:We retrospectively investigated patients who underwent emergent CA for AF during hospitalization for acute HF in 2018-2024. Arrhythmia recurrence was the primary endpoint. The combination of arrhythmia recurrence, HF hospitalization, and all-cause death was the secondary endpoint. Patients were censored 1 year after the index procedure. We included 46 patients, 35% females, with median age of 67 [interquartile rage: 61, 72] years and left ventricular ejection fraction (LVEF) of 25 [23, 28]%. Thermal CA was performed in 14 patients, and pulsed field ablation (PFA) in 32 patients. Procedure time was significantly shorter with PFA compared to thermal CA (77 [57, 91] vs. 166 [142, 200] minutes, p < 0.001). Fluoroscopy time was longer with PFA (9.5 [7.6, 12.0] vs. 3.9 [2.9, 6.0] minutes, p < 0.001), with a borderline trend towards higher radiation dose (75 [53, 170] vs. 50 [30, 94] μGy.m2, p = 0.056). Extrapulmonary ablation was frequent (86% and 84% for thermal CA and PFA, p > 0.9). The estimated freedom from the primary endpoint was 79% after PFA and 64% after thermal CA (p = 0.44). The estimated freedom from the secondary endpoint was 76% after PFA and 57% after thermal CA (p = 0.43). LVEF improved by 24% ± 2% (p < 0.001) in patients with the first manifestation of HF and by 14% ± 4% (p = .004) in patients with decompensated HF diagnosed earlier. CONCLUSIONS:Emergent CA of AF during acute HF hospitalization is safe and associated with improved LVEF and good clinical outcomes. In the PFA era, the rate of these procedures is progressively increasing as they are readily available and easy to perform compared to thermal ablation.

INTRODUCTION:Pulsed electric field (PEF) has emerged as a promising energy source for catheter ablation of atrial fibrillation (AF). However, data regarding the in-vivo effect of PEF energy on erythrocytes during AF ablation procedures are scarce. This study aimed to quantify the impact of PEF energy on erythrocyte damage during AF ablation by assessing specific hemolytic biomarkers. METHODS:A total of 60 patients (age: 68 years, males: 72%, serum creatinine: 91 µmol/L) with AF underwent catheter ablation of AF using PEF energy delivered by a multipolar pentaspline Farawave catheter (Farapulse, Boston Scientific, Inc.). Ablation beyond pulmonary vein isolation was performed at the operator's discretion. Peripheral venous blood was sampled for assessing the plasma levels of free hemoglobin (fHb), direct (conjugated) bilirubin, lactate dehydrogenase (LDH), and creatinine before, immediately after the ablation, and on the next day. RESULTS:Following the PEF ablation with duration of [median (interquartile range)] 75 (58, 95) min, with 74 (52, 92) applications and PVI only in 27% of patients, fHb, LDH, and direct bilirubin significantly increased, from 40 (18, 65) to 493 (327, 848) mg/L, from 3.1 (2.6, 3.6) to 6.8 (5.0, 7.9) µkat/L, and from 12 (9, 17) to 28 (16, 44) µmol/L, respectively (all p < .0001). A strong linear correlation was found between the peak fHb and the number of PEF applications (R = 0.81, p < .001). The major hemolysis (defined as fHb >500 mg/L) was predicted by the number of PEF applications with the corresponding area under the receiver operating characteristic curve of 0.934. The optimum cut-off value of >74 PEF applications predicted the major hemolysis with 89% sensitivity and 87% specificity. CONCLUSION:Catheter ablation of AF using PEF energy delivered from a pentaspline catheter is associated with significant intravascular hemolysis. More than 74 PEF applications frequently resulted in major hemolysis. However, the critical amount of PEF energy that may cause kidney injury in susceptible patients remains to be investigated.

Aims Patients with structural heart disease (SHD) undergoing catheter ablation (CA) for ventricular tachycardia (VT) are at considerable risk of periprocedural complications, including acute haemodynamic decompensation (AHD). The PAINESD score was proposed to predict the risk of AHD. The goal of this study was to validate the PAINESD score using the retrospective analysis of data from a large-volume heart centre. Methods and results Patients who had their first radiofrequency CA for SHD-related VT between August 2006 and December 2020 were included in the study. Procedures were mainly performed under conscious sedation. Substrate mapping/ablation was performed primarily during spontaneous rhythm or right ventricular pacing. A purposely established institutional registry for complications of invasive procedures was used to collect all periprocedural complications that were subsequently adjudicated using the source medical records. Acute haemodynamic decompensation triggered by CA procedure was defined as intraprocedural or early post-procedural (<12 h) development of acute pulmonary oedema or refractory hypotension requiring urgent intervention. The study cohort consisted of 1124 patients (age, 63 +/- 13 years; males, 87%; ischaemic cardiomyopathy, 67%; electrical storm, 25%; New York Heart Association Class, 2.0 +/- 1.0; left ventricular ejection fraction, 34 +/- 12%; diabetes mellitus, 31%; chronic obstructive pulmonary disease, 12%). Their PAINESD score was 11.4 +/- 6.6 (median, 12; interquartile range, 6-17). Acute haemodynamic decompensation complicated the CA procedure in 13/1124 = 1.2% patients and was not predicted by PAINESD score with AHD rates of 0.3, 1.8, and 1.1% in subgroups by previously published PAINESD terciles (<9, 9-14, and >14). However, the PAINESD score strongly predicted mortality during the follow-up. Conclusion Primarily substrate-based CA of SHD-related VT performed under conscious sedation is associated with a substantially lower rate of AHD than previously reported. The PAINESD score did not predict these events. The application of the PAINESD score to the selection of patients for pre-emptive mechanical circulatory support should be reconsidered.

Abstract Funding Acknowledgements Type of funding sources: None. Background The most frequent complications of catheter ablation for atrial fibrillation (AF) are related to vascular access. Purpose Vascular complication rates of ultrasound-guided venipuncture (USGV) were analyzed and compared to historical controls (CTRL) with an anatomical landmark-guided approach. Methods The study cohort included 4646 consecutive patients (2330 and 2316 patients in USGV and CTRL groups, respectively). Clinical characteristics were as follows: age of 61±10 years, 67% males, 66% paroxysmal AF, CHA2DS2-VASc score of 2.0±1.4, 27% reablation, and procedure time of 208±69 min. Both femoral veins were cannulated with 2 and 2 sheaths (7, 11, and 2x 8.5 French) in the majority (>95%) of procedures. Major complications were defined as those requiring intervention (surgery, thrombin injection, or transfusion), or hematoma/bleeding with hemoglobin drop >30g/l, or condition prolonging hospitalization and/or resulting in re-hospitalization. They were extracted from the institutional tracking system for complications of invasive procedures and by a review of medical reports within the first 3 months of follow-up. Results There were 32 (1.38%) vs. 62 (2.66%) major complications related to vascular access in USGV and CTRL groups, respectively (Yates corrected Chi-square P=0.003), i.e. relative reduction of -48% in the USGV group. Surgical intervention was needed in 6 (0.26%) vs. 18 (0.77%) patients, respectively (Fisher exact test P=0.02), i.e. relative reduction of -64% in the USGV group. The differences remained significant after adjustment for baseline clinical characteristics. Multivariate analysis revealed that USGV strategy (P=0.0005), male gender (P=0.003), and less advanced age (P=0.0002) were significantly associated with lower complication rates. Conclusions USGV was associated with a statistically significant reduction of major vascular complications after catheter ablation for AF. This strategy also decreased the need for surgical correction of vascular complications. Ultrasound guidance can be recommended to improve the safety of femoral venous access.

Radiofrequency (RF) catheter ablation of anterior right ganglionated plexus (ARGP) is effectively used for sinus nodal denervation but it has also an impact on vagal modulation of the atrioventricular node (AVN). Ablation of the posteromedial left ganglionated plexus (PMLGP) is critical for the elimination of vagal input to the AVN. For the treatment of symptomatic functional AV block, the ARGP followed by PMLGP ablation is the usual ablation strategy.