BACKGROUND AND AIMS:Patients with heart failure with reduced ejection fraction (HFrEF) derive less benefit from cardiac resynchronization therapy (CRT) if they have coexisting atrial fibrillation (AF). Observational data suggest that atrioventricular node ablation (AVNA) may enhance CRT efficacy in this population. This trial aimed to evaluate the effect of AVNA compared with medical rate control therapy (MRCT) on CRT outcomes in patients with HFrEF and permanent AF. METHODS:The CAAN-AF trial was an international, prospective, multicentre, randomized controlled trial evaluating the impact of AVNA in patients with HFrEF, permanent AF, and CRT-defibrillators (CRT-D). Participants were randomly assigned (1:1) to AVNA or MRCT targeting a resting heart rate <90 bpm. All participants received device optimization. The primary endpoint was a composite of all-cause mortality and nonfatal heart failure events. Secondary endpoints included cardiovascular mortality, unplanned hospitalizations, ventricular arrhythmias requiring device therapy, 6-min walk distance (6MWD), and quality of life. RESULTS:With early termination of the trial due to futility, a total of 143 patients were randomized (67 to AVNA, 76 to MRCT). Baseline characteristics were similar across groups. No significant difference was found in the primary endpoint [47 vs. 46 events; incident rate ratio (IRR), 1.16; 95% confidence interval (CI), 0.60-2.24]. Secondary outcomes, including cardiovascular mortality (odds ratio, 1.93; 95% CI 0.60-6.20), unplanned hospitalizations (IRR, 1.01; 95% CI 0.71-1.74), ventricular arrhythmias requiring device therapy (IRR, 0.68; 95% CI 0.17-2.63), 6MWD, and SF-36 scores, also showed no significant differences. CONCLUSIONS:This randomized trial of patients with permanent AF and CRT-D found no evidence of a reduction in all-cause mortality and nonfatal heart failure events with AVNA compared with MRCT. TRIAL REGISTRATION:NCT01522898.

Background Therapeutic delivery with left bundle branch area pacing (LBBAP) has continued to grow. However, limited data exists with LBBAP in de novo ICD or CRT-D indicated patients. Objective The aim of this analysis was to assess longer-term outcomes with the OmniaSecure defibrillation lead for LBBAP in ICD and CRT-D indicated patients. Methods The Kaplan-Meier method was used to determine the study lead-related major complication and appropriate therapy delivery rates up to 12-months post-implant. Electrical performance was summarized. QRSd, LVEF, LVESVi and quality of life were characterized in LOT-CRT patients at baseline and 6 months. Results A total of 316 patients had a LBBAP implant attempt (age: 64.9±12.2 years; 29.1% female). Pacing capture threshold, impedance and R-wave amplitude remained stable (follow-up: 9.9±4.0 months). The freedom from study lead-related major complications at 6 and 12 months were 97.7% and 96.8%, respectively. At 1 year, 7.9% of patients received appropriate therapy (shock or ATP) and the inappropriate shock rate was 2.1%. For LOT-CRT patients (n=143), there was a significant reduction in paced QRSd at 6 months compared to intrinsic (p<0.001), improved LVEF from baseline to 6 months (p<0.001) and reduced LVESVi from baseline to 6 months (p<0.001). Additionally, QoL improved from baseline to 6 months (KCCQ: p<0.001; CCS: 85% improved or stabilized). Conclusions The final study results of the LEADR LBBAP clinical trial demonstrate a continued stable electrical performance, low rate of lumenless defibrillation lead-related major complications, and LOT-CRT therapy benefit when a lumenless defibrillation lead is implanted for LBBAP. Clinical Trial Registration Number NCT04863664

Dual-chamber pacemaker implantation restores atrioventricular synchrony, but it might be associated with alterations in ventricular mechanics and valvular function. The echocardiographic effects of dual-chamber pacing in contemporary practice remain incompletely characterized. We conducted a retrospective single-center study of patients who underwent dual-chamber pacemaker implantation and had transthoracic echocardiography performed before and after implantation in 2022. Changes in left ventricular ejection fraction (LVEF), ventricular and atrial functional parameters, strain-derived measures, and tricuspid regurgitation (TR) severity were assessed using paired statistical analyses. In total, 57 patients were included. The mean LVEF declined from 59.6

AIMS:Clinical studies with protocol-mandated workflow and monitoring have analysed performance of pulsed field ablation (PFA) for treating atrial fibrillation (AF). The FARADISE registry captures global use of the pentaspline PFA catheter in real-world clinical practice with a follow-up of 3 years. METHODS AND RESULTS:FARADISE is a prospective, non-randomized, multi-national registry (NCT05501873) that enrolled subjects clinically indicated for ablation using the pentaspline PFA catheter per medical judgement and hospital standard-of-care. Procedural characteristics, safety, and clinical effectiveness up to 12-months were collected. In total, 1158 AF patients received PFA across 48 centres in 21 countries (64 ± 11 years, 33% female, 90% de novo, 65% paroxysmal AF). Pulmonary vein isolation (PVI)-only procedures were performed in 80.8% of paroxysmal vs. 57.5% for non-paroxysmal patients (P < 0.01). Median procedure, left atrial dwell, and fluoroscopy times were 51[40-70], 31[24-41], and 12[8-17] min, respectively. The rate of early onset serious adverse events was 1.5% and did not differ by ablation strategy or AF indication. At 1-year, clinical effectiveness was 80.8% for paroxysmal AF and 67.7% for non-paroxysmal AF, with no difference within indication by lesion set (paroxysmal: 81.2% PVI-only vs. 79.0% PVI+, P = 0.65; non-paroxysmal: 67.5% PVI-only vs. 67.7% PVI+, P = 0.79). Acute results reinforce a short procedural learning curve with no difference in 1-year effectiveness by operator experience. CONCLUSION:The FARADISE registry provides a snapshot of real-world clinical use of the pentaspline PFA catheter. Acute results demonstrate favourable procedural and safety outcomes regardless of AF indication. One-year outcomes are encouraging, with no differences seen within indication based on ablation strategy.

ABSTRACT Background There is limited data on long‐term safety and efficacy of subcutaneous implantable cardioverter defibrillator (S‐ICD) in Asian patients with a lower body mass index (BMI) due to smaller body build. Methods We performed a 2 year prospective study in 5 Asian cities from May 2017 to May 2018 to investigate the safety and feasibility of S‐ICD for primary or secondary prevention of sudden cardiac death in an Asian population. Results We enrolled 75 S‐ICD recipients (77% males; age 49.6 ± 16.8 years) with a mean BMI of 24.6 ± 5.0 (range 15.9–40.9) with 67% (50/75) with BMI ≤ 23. The indications of S‐ICD were primary and secondary prevention in 26 (35%) and 49 (65%) patients, respectively. Among them, 51 patients suffer from ischemic (30, 59%) or nonischemic (21, 41%) cardiomyopathy, and 25 patients have channelopathies. Their mean left ventricular ejection fraction was 44.4 ± 15.1%. All patients had successful S‐ICD implantation with a mean procedural duration of 75.5 ± 28.1 min using conscious sedation in majority of patients (65/75, 87%); and defibrillation testing was performed in 62 patients (83%). After 2 years of follow‐up, 8 patients developed serious adverse events, including 4 deaths (2 asystole, 1 sepsis, 1 myocardial infarction), 2 ventricular tachycardia storm, 1 pocket infection, and 1 lead failure requiring replacement. Both patients with ventricular tachycardia storm received appropriate shocks, and no patient developed inappropriate shocks. Conclusions S‐ICD implantation for both primary and secondary prevention of sudden cardiac death was found to be safe in an Asian population, including those with a low BMI, and was associated with a low rate of device‐related complications.

Background Comprehensive data on patients at high risk of sudden cardiac death (SCD) in emerging countries are lacking. The aim was to deepen our understanding of the SCD phenotype and identify risk factors for death among patients at high risk of SCD in emerging countries. Methods Patients who met the class I indication for implantable cardioverter-defibrillator (ICD) implantation according to guideline recommendations in 17 countries and regions underrepresented in previous trials were enrolled. Countries were stratified by the WHO regional classification. Patients were or were not implanted with an ICD at their discretion. The outcomes were all-cause mortality and SCD. Results We enrolled 4222 patients, and 3889 patients were included in the analysis. The mean follow-up period was 21.6 ± 10.2 months. There were 433 (11.1%) instances of all-cause mortality and 117 (3.0%) cases of SCD. All-cause mortality was highest in primary prevention (PP) patients from Southeast Asia and secondary prevention (SP) patients from the Middle East and Africa. The SCD rates among PP and SP patients were both highest in South Asia. Multivariate Cox regression modelling demonstrated that in addition to the independent predictors identified in previous studies, both geographic region and ICD use were associated with all-cause mortality in patients with high SCD risk. Primary prophylactic ICD implantation was associated with a 36% (HR = 0.64, 95% CI 0.531–0.802, p < 0.0001) lower all-cause mortality risk and an 80% (HR = 0.20, 95% CI = 0.116–0.343, p < 0.0001) lower SCD risk. Conclusions There was significant heterogeneity among patients with high SCD risk in emerging countries. The influences of geographic regions on patient characteristics and outcomes were significant. Improvement in increasing ICD utilization and uptake of guideline-directed medical therapy in emerging countries is urgent. Trial registration ClinicalTrials.gov, NCT02099721.

Background Advances in leadless pacemaker technology have enabled accelerometer-based atrioventricular (AV) synchronous pacing by sensing atrial mechanical contraction. Objectives To report performance of the Micra AV leadless pacemaker from the worldwide Micra AV post-approval registry (PAR) through 12-months. Methods The Micra AV PAR is a prospective single-arm observational registry designed to assess safety and effectiveness of Micra AV in a real-world setting. For the present interim analysis, major complications and system revisions through 12-months were summarized and compared to a historical cohort of 2,667 transvenous dual-chamber pacing patients. Results The device was successfully implanted in 796 of 801 patients (99.4%) at 97 centers in 19 countries. Micra AV patients were older (74.1 vs. 71.1 years, P<0.0001) with a higher incidence of renal disease (22.3% vs. 9.8%, P<0.0001) compared to transvenous dual-chamber patients. Through 12-months, the major complication rate was 3.7% in Micra AV patients compared to 8.8% in transvenous dual-chamber patients (hazard ratio [HR]: 0.42, 95% confidence interval [CI]: 0.28-0.61; P<0.001). The system revision rate was 1.5% in Micra AV patients compared to 5.5% for transvenous dual-chamber patients (HR: 0.25, 95% CI: 0.13-0.47; P<0.001); this reduction was largely driven by the absence of lead dislodgements requiring revision. Median AV synchrony index was 79.4% (IQR:65.2%-86.4%) among patients paced >90%. Conclusions The Micra AV leadless pacemaker was implanted with a high rate of success in patients with multiple co-morbidities, with a significantly lower rate of complications and system revisions through 12-months compared to a historical cohort of patients with transvenous dual-chamber pacemakers.

Abstract Aims The HINODE study aimed to analyse rates of mortality, appropriately treated ventricular arrhythmias (VA), and heart failure in Japanese patients and compared with those in Western patients. Methods and results After treatment decisions following contemporary practice in Japan, patients were prospectively enrolled into four cohorts: (i) internal cardioverter‐defibrillator (ICD), (ii) cardiac resynchronization therapy (CRT) defibrillator (CRT‐D), (iii) standard medical therapy (‘non‐device’: ND), or (iv) pacing (indicated for CRT; received pacemaker or CRT pacing). Cohorts 1–3 required a left ventricular ejection fraction ≤35%, a history of heart failure, and a need for primary prevention of sudden cardiac death based on two to five previously identified risk factors. Endpoint outcomes were adjudicated by the independent committees. ICD and CRT‐D cohorts, considered as high‐voltage (HV) cohorts, were pooled for Kaplan–Meier analysis and propensity‐matched to Multicenter Automatic Defibrillator Implantation Trial‐Reduce Inappropriate Therapy (MADIT‐RIT) arm B and C patients. The study enrolled 354 patients followed for 19.6 ± 6.5 months, with a minimum of 12 months. Propensity‐matched HV cohorts showed comparable VA (P = 0.61) and mortality rates (P = 0.29) for HINODE and MADIT‐RIT. The ND cohort presented a high crossover rate to ICD therapy (6.1%, n = 7/115), and the CRT‐D cohort showed elevated mortality rates. The pacing cohort revealed that patients implanted with pacemakers had higher mortality (26.0%) than those with CRT‐Pacing (8.4%, P = 0.05). Conclusions The mortality and VA event rates of landmark trials are applicable to patients with primary prevention in Japan. Patients who did not receive guideline‐indicated CRT devices had poor outcomes.

Background: Data on patients in emerging countries at high risk of sudden cardiac death (SCD) are lacking. The Improve SCA registry is the first prospective, global registry to evaluate this population.Methods: Patients who met guideline recommendations for implantable cardioverter-defibrillator (ICD) implantation were enrolled in 17 countries and regions in regions underrepresented in previous trials. Countries were stratified by WHO regional classification and income level based on the World Bank classification system. Primary outcomes were all-cause mortality and SCD.Findings: We enrolled 4,222 patients and 3,889 patients were included in the analysis. The mean follow-up period was 21·6±10·2 months. There were 433 (11·1%) instances of all-cause mortality and 117 (3·0%) SCD. All-cause mortality was highest in primary prevention (PP) patients from Southeast Asia (Southeast Asia/Europe, HR=3·18, 95%CI: 1·14-8·91, P=0·0275), while it was highest in secondary prevention (SP) patients from the Middle East and Africa (MEA) (MEA/Europe, HR=5·1, 95%CI 1·13-23·0, P=0·0341). The SCD rate of PP and SP patients was highest in South Asia. All-cause mortality in PP patients from upper middle income (UMI) countries was higher than high income (HI) (HR=1·38, 95% CI: 1·04-1·84, p=0·0276) and lower middle income countries (LMI) (HR=1·563, 95% CI: 1·18-2·08, p=0·0021). SCD rates of PP and SP patients of LMI countries were higher than UMI and HI (p<0·0001).Interpretation: There was significant heterogeneity among high SCD risk patients in emerging countries. Influences of both geography and income level on patient outcomes were significant. These findings emphasize the need to increase ICD/CRT-D utilization in emerging countries.Trial Registration: ClinicalTrials.gov identifier: NCT02099721Funding: This study was funded by Medtronic Inc.Declaration of Interest: S. Zhao declare no conflicts of interest. S. Zhang: speakers bureau/consulting fees: Boston Scientific, Medtronic, St. Jude Medical, Biotronik, steering committee fees: Medtronic; CK Ching: speaker fees/steering committee fees: Medtronic; D. Huang: speaker/consultant fees: Boston Scientific, St. Jude Medical; YB Liu: speaker fees/steering committee fees, Medtronic; DA. Rodriguez: proctor/lecture fees: Boston Scientific, proctorship: Biosense Webster, St. Jude Medical/Abbott, steering committee fees: Medtronic; Azlan Hussin: speaker fees/steering committee fees, Medtronic; YH. Kim: steering committee fees: Medtronic; AR. Chasnoits: steering committee fees: Medtronic; J. Cerkvenik: Employment: Medtronic; D. Lexcen: Employment: Medtronic; K. Muckala: Employment: Medtronic; M. Brown: Employment: Medtronic; A. Cheng: Employment: Medtronic; XH Zhou: Employment: Medtronic; B. Singh: steering committee fees: MedtronicEthical Approval: The protocol was approved by the ethics committee at each participating institution and associated national and local regulatory agencies. All patients provided writteninformed consent before undergoing study procedures.

Background: Despite a proven mortality benefit in primary prevention (PP) patients, the utilization of implantable cardioverter-defibrillators (ICD) and cardiac resynchronization therapy-defibrillators (CRT-D) remains low in many geographies. Purpose: The objective of this analysis was to examine the mortality benefit in PP patients by guideline-indicated device type: implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D). Methods: Improve SCA was a prospective, non-randomized, non-blinded multicenter trial that enrolled patients from regions where ICD utilization is low. PP patient’s CRT-D or ICD eligibility was based upon the 2008 ACC/AHA/HRS and 2006 ESC guidelines. Mortality was assessed according to guideline-indicated device type comparing implanted and non-implanted patients. Cox proportional hazards methods were used, adjusting for known factors affecting mortality risk. Results: Among 2,618 PP patients followed for a mean of 20.8 ± 10.8 months, 1,073 were indicated for a CRT-D, and 1,545 were indicated for an ICD. PP CRT-D-indicated patients who received CRT-D therapy had a 58% risk reduction in mortality compared to those without implant (adjusted HR 0.42, 95% CI: 0.28-0.61, P<0.0001). PP patients with an ICD indication had a 43% risk reduction in mortality with an ICD implant compared with no implant (adjusted HR 0.57, 95% CI: 0.41-0.81, P=0.002). Conclusions: This analysis confirms the mortality benefit of adherence to guideline-indicated implantable defibrillation therapy for PP patients in geographies where ICD therapy was underutilized. These results affirm that medical practice should follow clinical guidelines when choosing therapy for PP patients who meet the respective defibrillator device implant indication.

BACKGROUND Implantable cardioverter-defibrillators (ICDs) are underutilized in Asia, Latin America, Eastern Europe, the Middle East, and Africa. The Improve SCA Study is the largest prospective study to evaluate the benefit of ICD therapy in underrepresented geographies. This analysis reports the primary objective of the study. OBJECTIVES The objectives of this study was to determine whether patients with primary prevention (PP) indications with specific risk factors (1.5PP: syncope, nonsustained ventricular tachycardia, premature ventricular contractions >10/h, and low ventricular ejection fraction < 25%) are at a similar risk of life-threatening arrhythmias as patients with secondary prevention (SP) indications and to evaluate all-cause mortality rates in 1.5PP patients with and without devices. METHODS A total of 3889 patients were included in the analysis to evaluate ventricular tachycardia or fibrillation therapy and mortality rates. Patients were stratified as SP (n - 1193) and patients with PP indications. The PP cohort was divided into 1.5PP patients (n - 1913) and those without any 1.5PP criteria (n 5 783). The decision to undergo ICD implantation was left to the patient and/or physician. The Cox proportional hazards model was used to compute hazard ratios. RESULTS Patients had predominantly nonischemic cardiomyopathy. The rate of ventricular tachycardia or fibrillation in 1.5PP patients was not equivalent (within 30%) to that in patients with SP indications (hazard ratio 0.47; 95% confidence interval 0.38-0.57) but was higher than that in PP patients without any 1.5PP criteria (hazard ratio 0.67; 95% confidence interval 0.46-0.97) (P = .03). There was a 49% relative risk reduction in all-cause mortality in ICD implanted 1.5PP patients. In addition, the number needed to treat to save 1 life over 3 years was 10.0 in the 1.5PP cohort vs 40.0 in PP patients without any 1.5PP criteria. CONCLUSION These data corroborate the mortality benefit of ICD therapy and support extension to a selected PP population from underrepresented geographies.

Introduction: Cardiac Resynchronization Therapy (CRT) is used to treat heart failure patients with left bundle branch block (LBBB).With good right ventricular (RV) conduction (RVc), adaptive atrioventricular delay (AVD) using left-ventricular (LV) pacing, no RV pacing, is used to extend device longevity.Simpler fixed AVD LV-only is discussed here.Methods: Three LBBB CRT pacemaker (CRT-P) patients with good RVc were reprogrammed to fixed AVD LV-only to extend device longevity utilizing intrinsic RVc.With the RVs triggering feature when an early RVs is detected (before LVp) an LVp is immediately triggered, forcing resynchronization.An RVs arriving after the LVp is not detected.The patients were implanted with 3 different CRT-P models from a manufacturer.Follow-up (FU) durations: 4 years, 8 & 8 months.FUs are performed every 2-12 months to increase data collection, we initiated home remote monitoring (RM) for nightly statistics.Result: Extending daily the LV AVD to 300 ms, the CRT-Ps measure the intrinsic atrial sense/pace to ventricular sense (Ax-Vs) intervals.At the start of LV-only, from prior biventricular pacing, the intervals were found to be spread over the 0-300 ms range.With fixed AVD LV-only, autonomic nervous system, ANS, optimization is recognized when the intervals coalesce into ≤2 adjacent 10 bpm bins from then on.In the late model CRT-P, we were able to aggressively remote schedule the full FUs with electrogram (EGM).Each full FU includes 10 seconds each for normal rhythm, enhanced sensing with LV AVD to 300 ms, fast atrial pacing.EGMs were also received for atrial fibrillation (AF) episodes.Over 4 months of RM, 18 reports with 3 channel EGMs were received: 11 periodic FUs, 7 short 12 seconds AF records.In this abstract we focus on this patient.The paper will discuss the other 2 patients from whom we received 5 + 19 and 3 + 0 EGM records.The daily RM data include %As-Vs, and atrial rate.The Vs are actually RVs.With LV AVD of 125 ms, the histogram of the daily %As-Vs (Ap = 0%) with early RVs and triggered LVp is shown in Figure 1.The median daily %As-Vs is 11%.The 13 times the daily %As-Vs are >30% cannot be random, since each corresponds to >7 hours.The associated atrial rates are also high.This shows active dromotropic RVc modulation.Figure 2 shows the distribution of the %As-Vs vs the daily atrial rate.Dromotropic RVc shortening allows more early RVs at high atrial rates, increasing %As-RVs.From the 18 EGM records, As-RVs intervals are measured.Figure 3 summarizes the results.All 3 regression curves exhibit dromotropic shortening at increased atrial rates.F I G U R E 2 Distribution of daily As-RVs vs average daily atrial rate 95

Introduction : Dislodgements of left ventricular (LV) leads are still a challenging problem in cardiac resynchronization therapy (CRT). The Attain Stability Quad (ASQuad) MRI SureScan Model 4798 steroid-eluting, quadripolar LV lead has a side-helix to enable the lead to be actively fixated to the vessel wall. The uniquely designed active fixation can be advantageous in vessels that are wide or have short take-offs. Further, the helix easily elongates to allow for future extraction.

### Patient Initials or Identifier Number NSI ### Relevant Clinical History and Physical Exam We described a 25-year-old patient without past medical history who was electively admitted for premature ventricular complex (PVC) ablation. She initially presented with frequent palpitation and