Myocardial injury and inflammation following pulsed-field ablation and very high-power short-duration ablation for atrial fibrillation.

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.

Electrical isolation of the right ventricular outflow tract in idiopathic ventricular tachycardia: a case report.

Background: Ventricular tachycardia (VT) originating in the right ventricular outflow tract (RVOT) is the most common form of idiopathic VT. Catheter ablation of right ventricular outflow tract tachycardia (RVOT-VT) is associated with high success rates. However, non-inducibility of VT on electrophysiological (EP) study can severely impact ablation outcome. We describe a novel catheter ablation strategy which proved feasible and safe in a case of highly symptomatic, non-inducible RVOT-VT. Case summary: A 51-year-old male with a history of non-sustained VT (NSVT) was referred to our hospital after two syncopal episodes resulting in collapse. Upon admission, a cluster of monomorphic NSVT (250-270 b.p.m.) resulted in haemodynamic instability and required transfer to the intensive care unit. On twelve-lead electrocardiogram, NSVT showed inferior axis and left bundle branch block, suggestive of RVOT-VT. Diagnostic workup including echocardiography, coronary angiography, and late enhancement computed tomography (CT) revealed no evidence of structural heart disease. On two EP studies, non-inducibility of clinical VT despite repeated ventricular pacing and isoproterenol infusion rendered precise mapping of triggered activity unfeasible. Therefore, a bailout ablation strategy was developed by performing a circumferential electrical RVOT isolation using a 3.5 mm irrigated-tip ablation catheter under the guidance of high-density electroanatomic mapping (CARTO® 3) and CT reconstruction of cardiac anatomy. No procedural complications occurred, and the patient remained arrhythmia-free during a 6-month follow-up period. Discussion: Catheter ablation is a first-line therapy for symptomatic and drug-refractory idiopathic RVOT-VT. Non-inducibility of RVOT-VT represents a relevant limitation for successful ablation which might be overcome by electrical RVOT isolation as a bailout ablation strategy.

Safety profile and long-term efficacy of very high-power short-duration (60-70 W) catheter ablation for atrial fibrillation: results of a large comparative analysis.

AIMS: 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). METHODS AND RESULTS: 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). CONCLUSION: vHPSD ablation is as safe as conventional ablation and is associated with an improved long-term efficacy in persistent AF.

Early arrhythmia recurrence after catheter ablation for persistent atrial fibrillation: is it predictive for late recurrence?

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.