Alan Bulava

Aims: A dual-energy ablation system was developed to optimize targeted energy delivery via a flexible-tip, contact-force sensing catheter with electroanatomic mapping integration. This is the first report of long-term safety and effectiveness results of this system for ablation of paroxysmal atrial fibrillation (PAF). Methods and results: The FOCALFLEX study is a prospective, multicentre study. Patients with PAF were enrolled between August 2024 and January 2025, with 144 patients (62.0 ± 10.0 years, 62.6% male) undergoing ablation with the TactiFlex PFA System at 21 sites worldwide. Primary safety and effectiveness endpoints were the rate of pre-defined serious adverse events within 7 days and the 6-month freedom from documented AF/AFL/AT episodes >30 s after a 90-day blanking period. Pulmonary vein isolation (PVI) was performed in each case with pulsed field required for posterior left atrium (LA) ablation and radiofrequency (RF) for cavotricuspid isthmus or near coronary arteries. Non-PV targets and modality were at physician’s discretion. Acute effectiveness was confirmed via entrance block and post-ablation LA voltage map after a 20-min waiting period and was achieved in 99.6% (566/568) of treated PVs with 95.5 ± 37.1 pulsed field ablation (PFA) applications/patients. Procedure, fluoroscopy, LA dwell, and PV ablation times were 112.2 ± 29.5, 7.6 ± 5.7, 81.1 ± 19.7, and 47.4 ± 16.4 min, respectively. There were two (1.4%) primary safety events. At 6 months, 81.0% of subjects were free from documented arrhythmia recurrence and the protocol-defined primary effectiveness rate was 79.6%. There was one repeat ablation (0.7%) after the blanking period through 6 months. Conclusion: The FOCALFLEX study results demonstrate safety and effectiveness of a novel dual-mode RF/PFA system through 6 months of follow-up to treat symptomatic, recurrent PAF. Clinical trial registration: ClinicalTrials.gov Identifier: NCT06271967

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.

Background: The alert-based HeartInsight algorithm predicts risk of worsening heart failure hospitalisations (WHFHs) by evaluating temporal trends of seven physiologic parameters obtained through automatic daily remote monitoring of implantable cardioverter-defibrillators. The aim of the present study was to evaluate the predictive performance of HeartInsight in a larger and more heterogeneous meta-cohort of patients, incorporating newer device generations and including patients managed with the most recent guideline-directed medical therapy (GDMT). Methods: The HeartInsight algorithm was retrospectively applied to data from four clinical trials in which WHFH events were adjudicated by independent external boards and remote monitoring was activated to provide relevant parameter trends. The analysis comprised 1352 patients with New York Heart Association (NYHA) class II/III, and no long-standing atrial fibrillation. Results: During a median follow-up of 599 days, 110 patients (median age 68 years (IQR, 61–75), 75.7% male) had a total of 165 WHFHs. The estimated sensitivity of WHFH prediction, as determined by generalised estimating equations, was 51.5% (95% CI 43.0% to 59.9%). The false alert rate was 0.85 per patient-year, the median alerting time was 34 days (IQR, 16–78) and the specificity was 81.4% (95% CI 80.4 to 82.4%). The results were verified in the multivariable analysis with two adjusting covariates (newer/older device generation and quadruple/other GDMT) and in the univariable analysis of prespecified patient subgroups according to NYHA class, aetiology and sex, showing no significant differences. Conclusions: Study results underscore the robustness of the predictive algorithm in a heterogeneous and contemporarily managed heart failure population.

OBJECTIVES: The CEASE-AF trial demonstrated that epicardial-endocardial hybrid ablation (HA) had superior effectiveness compared to endocardial catheter ablation (CA) for non-paroxysmal atrial fibrillation (AF), without significantly increasing major complications during a 12-month period. Most contemporary AF ablation trials have not evaluated durability beyond 12 months. Therefore, 24-month effectiveness and safety of HA and CA are compared. METHODS: CEASE-AF is a prospective, multicentre, randomized trial. Patients 18–75 years of age with symptomatic, drug refractory persistent AF and left atrial diameter >4.0 cm or long-standing persistent AF were randomized 2:1 to HA (posterior wall and pulmonary vein isolation with left atrial appendage exclusion) or CA (pulmonary vein isolation). Secondary effectiveness was freedom from AF/atrial flutter/atrial tachycardia off class I/III anti-arrhythmic drugs except for those who previously failed at doses not exceeding those previously failed through a 24-month follow-up period. Major complications and reinterventions were evaluated. RESULTS: The intention-to-treat population was 102 patients with HA and 52 patients with CA. Seventy-five percent were male, 80.5% had persistent AF and 19.5% had long-standing persistent AF, with a mean age of 60.7 ± 7.9 years. Effectiveness for 24 months was 66.3% (63/95) with HA and 33.3% (17/51) with CA [absolute difference 33.0% (95% confidence interval 14.3%, 48.3%; P < 0.001)]. Major complication rates were 10.8% (11/102) with HA and 9.6% (5/52) with CA (P = 1.0), and fewer patients had reinterventions after HA than CA [18.9% (18/95) vs 52.9% (27/51), P < 0.001]. CONCLUSIONS: CEASE-AF demonstrated that the 32.4% absolute benefit of HA over CA for 12 months was durable for 24 months at 33% with continued similar safety rates and fewer reinterventions after HA (funded by AtriCure, Inc.; NCT02695277). Clinicaltrials.gov registration: NCT02695277

Aims: A pulsed electric field (PF) energy source is a novel potential option for catheter ablation of ventricular arrhythmias (VAs) as it can create deeper lesions, particularly in scarred tissue. However, very limited data exist on its efficacy and safety. This prospective observational study reports the initial experience with VA ablation using focal PF. Methods and results: The study population consisted of 44 patients (16 women, aged 61 ± 14years) with either frequent ventricular premature complexes (VPCs, 48%) or scar-related ventricular tachycardia (VT, 52%). Ablation was performed using an irrigated 4 mm tip catheter and a commercially available PF generator. On average, 16 ± 15 PF applications (25 A) were delivered per patient. Acute success was achieved in 84% of patients as assessed by elimination of VPC or reaching non-inducibility of VT. In three cases (7%), a transient conduction system block was observed during PF applications remotely from the septum. Root analysis revealed that this event was caused by current leakage from the proximal shaft electrodes in contact with the basal interventricular septum. Acute elimination of VPC was achieved in 81% patients and non-inducibility of VT in 83% patients. At the 3-month follow-up, persistent suppression of the VPC was confirmed on Holter monitoring in 81% patients. In the VT group, the mean follow-up was 116 ± 75 days and a total of 52% patients remained free of any VA. Conclusion: Pulsed electric field catheter ablation of a broad spectrum of VA is feasible with acute high efficacy; however, the short-term follow-up is less satisfactory for patients with scar-related VT.

Objectives: Current recommendations support surgical treatment of atrial fibrillation (AF) in patients indicated for cardiac surgery. These procedures are referred to as concomitant and may be carried out using radiofrequency energy or cryo-ablation. This study aimed to assess the electrophysiological findings in patients undergoing concomitant cryo-ablation. Methods: Patients with non-paroxysmal AF undergoing coronary artery bypass grafting and/or valve repair/replacement were included in the trial if concomitant cryo-ablation was part of the treatment plan according to current guidelines. The patients reported in this study were assigned to undergo staged percutaneous radiofrequency catheter ablation (PRFCA), i.e., hybrid treatment, as a part of the SURHYB trial protocol. Results: We analyzed 103 patients who underwent PRFCA 105 ± 35 days after surgery. Left and right pulmonary veins (PVs) were found isolated in 65 (63.1%) and 63 (61.2%) patients, respectively. The LA posterior wall isolation and mitral isthmus conduction block were found in 38 (36.9%) and 18 (20.0%) patients, respectively. Electrical reconnections (gaps) in the left PVs were more often localized superiorly than inferiorly (57.9% vs. 26.3%, P = 0.005) and anteriorly than posteriorly (65.8% vs. 31.6%, P = 0.003). Gaps in the right PVs were more equally distributed anteroposteriorly but dominated in superior segments (72.5% vs. 40.0%, P = 0.003). There was a higher number of gaps on the roof line compared to the inferior line (131 (67.2%) vs. 67 (42.2%), P < 0.001). Compared to epicardial cryo-ablation, endocardial was more effective in creating PVs and LA posterior wall isolation (P < 0.05). Cryo-ablation using nitrous oxide (N₂0) or argon (Ar) gas as cooling agents was similarly effective (P = NS). Conclusions: The effectiveness of surgical cryo-ablation in achieving transmural and durable lesions in the left atrium is surprisingly low. Gaps are located predominantly in the superior and anterior portions of the PVs and on the roof line. Endocardial cryo-ablation is more effective than epicardial ablation, irrespective of the cooling agent used.

Background: Hybrid Ablation for atrial fibrillation (AF) combines epicardial and endocardial ablation through a Heart Team approach to target durable, transmural isolation of the pulmonary veins (PV) and left atrial posterior wall (LAPW). While the primary efficacy endpoint at 12 months was met with a significant benefit increase for hybrid ablation, we now report the midterm durability of those results. Purpose: To evaluate 24-months safety and effectiveness of Hybrid Ablation with left atrial appendage exclusion (LAAE) versus Catheter Ablation in patients with persistent AF/enlarged left atrium and longstanding persistent AF (LSPAF). Methods: CEASE-AF is a prospective, multi-center, 2:1 randomized controlled trial. Eligible patients were 18-75 years of age, had symptomatic, drug-refractory persistent AF and enlarged left atrium (>4 cm) or LSPAF, and were undergoing a first ablation. Hybrid Ablation consisted of two stages: thoracoscopic epicardial radiofrequency (RF) ablation for PV and LAPW isolation and epicardial LAAE followed by endocardial ablation 91-180 days later. Catheter Ablation consisted of minimum PV isolation by endocardial RF ablation, and repeat ablation was allowed between 91-180 days. In both arms, additional lesions were permitted according to institutional practices. Effectiveness was freedom from AF/atrial flutter (AFL)/atrial tachycardia (AT) off anti-arrhythmic drugs (AAD) (except AADs not exceeding doses which previously failed) and was assessed through 48-h Holter monitoring reviewed by an independent core laboratory blinded to the study. Safety was major adverse events throughout the study, adjudicated by an independent Clinical Events Committee. Results: There were 102 Hybrid Ablation and 52 Catheter Ablation patients; 26% were female, mean age was 60.7±7.9 years, mean LAD was 4.7±0.4 cm, and 19% had LSPAF with no differences between arms. The 12- and 24-month results are shown for comparison (Table). Through 24-months, effectiveness was 66.3% (63/95) in the Hybrid Arm and 33.3% (17/51) in the Catheter Arm (absolute difference 33.0% [95% CI 14.3%, 48.3%; p<0.001]). Major adverse event rates through 24-months were statistically similar at 10.8% (11/102) in the Hybrid Arm and 9.6% (5/52) in the Catheter Arm (p=1.0). Through 24-months, repeat ablations were performed in 7.4% (7/95) of the Hybrid Arm versus 37.3% (19/51) of the Catheter Arm (p<0.001), and cardioversions were performed in 14.7% (14/95) of the Hybrid Arm versus 29.4% (15/51) of the Catheter Arm (p=0.034) Conclusions: CEASE-AF demonstrated that superior effectiveness of Hybrid Ablation including LAAE versus Catheter Ablation was durable through 24-month follow-up, with 33% absolute improvement in freedom from AF/AFL/AT. Safety rates continued to be similar between arms. Three-year follow-up is ongoing.

Objectives Current recommendations support surgical treatment of atrial fibrillation (AF) in patients indicated for cardiac surgery. These procedures are referred to as concomitant and may be carried out using radiofrequency energy or cryo-ablation. This study aimed to assess the electrophysiological findings in patients undergoing concomitant cryo-ablation. Methods Patients with non-paroxysmal AF undergoing coronary artery bypass grafting and/or valve repair/replacement were included in the trial if concomitant cryo-ablation was part of the treatment plan according to current guidelines. The patients were assigned to undergo radiofrequency catheter ablation (RFCA), i.e., hybrid treatment, as a part of the multicenter trial. Results We analyzed 103 patients who underwent RFCA 105±35 days after surgery. Left and right pulmonary veins (PVs) were found isolated in 65 (63.1%) and 63 (61.2%) patients, respectively. The LA posterior wall isolation and mitral isthmus conduction block were found in 38 (36.9%) and 18 (20.0%) patients, respectively. Electrical reconnections (gaps) in the left PVs were more often localized superiorly than inferiorly (57.9% vs. 26.3%, P=0.005) and anteriorly than posteriorly (65.8% vs. 31.6%, P=0.003). Gaps in the right PVs were more equally distributed anteroposteriorly but dominated in superior segments (72.5% vs. 40.0%, P=0.003). There was a higher number of gaps on the roof line compared to the inferior line (131 (67.2%) vs. 67 (42.2%), P 20) or argon (Ar) gas as cooling agents was similarly effective (P=NS). Conclusions The effectiveness of surgical cryo-ablation in achieving transmural and durable lesions in the left atrium is surprisingly low. Gaps are located predominantly in the superior and anterior portions of the PVs and on the roof line. Endocardial cryo-ablation is more effective than epicardial ablation, irrespective of the cooling agent used.