Atrial fibrillation (AF) is a very common arrhythmia that mainly affects older individuals. The mechanism of atrial fibrillation is complex and is related to the pathogenesis of trigger activation and the perpetuation of arrhythmia. The pulmonary veins in the left atrium arei confirm that onfirm the most common triggers due to their distinct anatomical and electrophysiological properties. As a result, their electrical isolation by ablation is the cornerstone of invasive AF treatment. Multiple factors and comorbidities affect the atrial tissue and lead to myocardial stretch. Several neurohormonal and structural changes occur, leading to inflammation and oxidative stress and, consequently, a fibrotic substrate created by myofibroblasts, which encourages AF perpetuation. Several mechanisms are implemented into daily clinical practice in both interventions in and the medical treatment of atrial fibrillation.

Aims: Temperature-controlled high-power short-duration (HPSD) radiofrequency catheter ablation for pulmonary vein isolation (PVI) utilizing a novel ablation catheter (QDOT Micro) with real-time assessment of catheter tip temperature aims for safer, more effective, and faster procedures. Methods and results: The peQasus study is a large European multicentre study set up to assess safety, acute efficacy, and outcomes of temperature-controlled HPSD-based PVI. The primary endpoints were safety, efficacy, and 12-month freedom from atrial tachyarrhythmias. Additionally, two strategies namely very HPSD (90 W for 4 s) only and a hybrid approach (HPSD with maximum of 50 W and vHPSD) were compared. A total of 1023 AF patients in 15 centres from nine European countries received PVI with the QDOT. Complete PVI was successfully achieved in all patients. In 699/1023 (68.3%), the vHPSD-only approach (vHPSD group) and in 324/ (31.7%) patients, the hybrid approach (hybrid group) was utilized. The mean procedure duration was 98.4 ± 37.4 min (vHPSD: 88.2 ± 34.9 min, hybrid: 117.4 ± 32.7 min, P < 0.001). The first-pass isolation rate of all PVs was 64% (vHPSD: 62.6%, hybrid: 67.1%, P = 0.187). Severe adverse events were observed in 1.7% (vHPSD: 1.6%, hybrid: 1.9%, P = 0.746). Twelve-month arrhythmia-recurrence-free survival was 77.1% (vHPSD: 76.8%, hybrid: 77.8%, P = 0.241). Conclusion: In this large multicentre study, temperature-controlled HPSD and vHPSD ablation via a novel ablation catheter provides safe and effective PVI with a relatively short procedure duration. Despite a shorter procedure time, no differences in terms of safety and freedom from arrhythmia recurrence were found irrespective of utilizing vHPSD or the hybrid approach.

Background: Biventricular pacing (BVP) is recommended for patients with heart failure (HF) who require cardiac resynchronization therapy (CRT). Left bundle branch area pacing (LBBAP) is a novel pacing strategy that appears to ensure better electrical and mechanical synchrony in these patients. Our aim was to systematically review and meta-analyze the existing evidence regarding the clinical outcomes of LBBAP-CRT compared with BVP-CRT. Methods: Medline, Embase, Cochrane Central Register of Controlled Trials and Web of Science databases were searched for studies comparing LBBAP-CRT with BVP-CRT. Outcomes were all-cause mortality, heart failure hospitalizations (HFH) and New York Heart Association (NYHA) class improvement. We included randomized controlled trials (RCTs) and observational studies with participants that had left ventricular ejection fraction (LVEF) ≤40% and (i) symptomatic HF or (ii) expected ventricular pacing >40%. Random and fixed effects models pairwise meta-analysis was conducted. Cochrane Risk of Bias 2 assessment tool (ROB 2.0) and the Newcastle–Ottawa scale (NOS) were used to assess the quality of the studies. Results: Eleven studies (10 observational studies and 1 RCT) with 3141 patients were included in the analysis. Compared with BVP-CRT, LBBAP-CRT was associated with lower risk of all-cause mortality (risk ratio (RR): 0.71, 95% CI: 0.57 to 0.87; p = 0.001), lower risk of HFH (RR: 0.59, 95% CI: 0.50 to 0.71; p < 0.00001) and more improvement in NYHA class (weighed mean difference (WMD): –0.36, 95% CI: –0.59 to –0.13; p < 0.00001) compared with patients who received BVP-CRT. Conclusions: Compared with BVP-CRT, receipt of LBBAP-CRT in patients with HF is associated with a lower risk of mortality, and HFH and greater improvement in NHYA class.