Maja Ivanovski

Background and Aims: Randomized evidence comparing conduction system pacing (CSP) and biventricular pacing (BVP) following atrioventricular node ablation in patients with refractory atrial fibrillation (AF) and heart failure (HF) remains limited. This study evaluated whether CSP with left bundle branch area pacing is non-inferior to BVP in patients undergoing atrioventricular node ablation. Methods: CONDUCT-AF was an investigator-initiated, multicentre, randomized trial conducted across 10 European centres. Patients with refractory AF, HF with left ventricular ejection fraction (LVEF) < 50%, narrow QRS duration (≤120 ms), and N-terminal pro-B-type natriuretic peptide > 600 ng/L were randomized 1:1 to CSP or BVP. The primary endpoint was the change in LVEF after 6 months, assessed by an independent core laboratory. Secondary endpoints included echocardiographic, clinical, and procedural outcomes. Analyses followed the intention-to-treat principle. Results: Eighty-two patients were randomized (mean age 72 ± 7 years, 46% male). At 6 months, LVEF improved similarly in CSP {from 36% [95% confidence interval (CI) 33–39] to 46% [95% CI 44–49]; P < .001} and BVP group [from 34% (95% CI 31–36) to 46% (95% CI 43–49); P < .001]. The between-group difference was .4% (95% CI −3.1–3.8; P = .002 for non-inferiority). Changes in left ventricular volumes, clinical parameters, and composite endpoint of worsening HF or cardiovascular death were comparable between groups. Paced QRS [mean difference −14 ms (95% CI −19 to −9; P < .001)] and procedural and fluoroscopy times were significantly shorter with CSP compared with BVP. Conclusions: In HF patients with refractory AF undergoing atrioventricular node ablation, CSP with left bundle branch area pacing was non-inferior to BVP for LVEF improvement at 6 months, providing comparable clinical outcomes and a favourable procedural profile.

Background: There are limited prospective randomized studies comparing left bundle branch area pacing (LBBAP) and biventricular (BiV) pacing for cardiac resynchronization therapy (CRT). Aim: The study tested whether LBBAP is noninferior to BiV pacing in patients with Class I indication for CRT. Methods: The CSP-SYNC study is an investigator-initiated, randomized, single-center study. Sixty-two patients were randomized 1:1 to LBBAP or BiV. The primary study endpoint was change in left ventricular ejection fraction (LVEF) at 6 months. Secondary endpoints included changes in echo and clinical parameters after 6 months and 12 months. Results: Thirty-one patients were randomized to each arm. Most patients were males (71%), and 32 % had ischemic cardiomyopathy. At 6 months, similar improvement of LVEF was observed in the LBBAP group compared to the BiV group (14.0% (95% CI: 11.2-16.8) in LBBAP vs. 8.5% (95% CI: 5.6-11.2) in BiV) with mean intergroup difference of 5.6% (95% CI: 1.6-9.5; P<0.001 for noninferiority). Both groups showed comparable decrease in LVESV (-64 ml (95% CI: -78 to -50) vs -40 ml (95% CI: -54 to -25) respectively, mean difference -24 ml (CI 95%: -44 to -4); P<0.001 for noninferiority), changes in 6-minute walk test (P<0.001 for noninferiority) and NYHA class (P=0.011 for noninferiority). Temporal trends of LV remodelling and heart failure hospitalization rates were also comparable. Conclusions: In patients with a Class I indication for CRT, LBBAP was noninferior to BiV pacing in improving LVEF and provided similar structural and electrical remodelling.

Primary prevention patients with ischaemic cardiomyopathy and chronic total occlusion of an infarct-related coronary artery (CTO) are at a particularly high risk of implantable cardioverter-defibrillator (ICD) therapy occurrence. The trial was designed to evaluate the efficacy of preventive CTO-related substrate ablation strategy in ischaemic cardiomyopathy patients undergoing primary prevention ICD implantation. The PREVENTIVE VT study was a prospective, multicentre, randomized trial including ischaemic patients with ejection fraction ≤40%, no documented ventricular arrhythmias (VAs), and evidence of scar related to the coronary CTO. Patients were randomly assigned 1:1 to a preventive substrate ablation before ICD implantation or standard therapy with ICD implantation only. The primary outcome was a composite of appropriate ICD therapy or unplanned hospitalization for VAs. Secondary outcomes included the primary outcome’s components, the incidence of appropriate ICD therapies, cardiac hospitalization, electrical storm, and cardiovascular (CV) mortality. Sixty patients were included in the study. During the mean follow-up of 44.7 ± 20.7 months, the primary outcome occurred in 5 (16.7%) patients undergoing preventive substrate ablation and in 13 (43.3%) patients receiving only ICD [hazard ratio (HR): 0.33; 95% confidence interval (CI): 0.12–0.94; P = 0.037]. Patients in the preventive ablation group also had fewer appropriate ICD therapies (P = 0.039) and the electrical storms (Log-rank: P = 0.01). While preventive ablation also reduced cardiac hospitalizations (P = 0.006), it had no significant impact on CV mortality (P = 0.151). Preventive ablation of the coronary CTO-related substrate in patients undergoing primary ICD implantation is associated with the reduced risk of appropriate ICD therapy or unplanned hospitalization due to VAs. Preventive ablation of coronary total occlusion-related substrate at the time of primary prevention defibrillator implantation is associated with a reduced risk of appropriate defibrillator therapy or unplanned hospitalization due to ventricular arrhythmias.