Automatic capture confirmation algorithms regularly evaluate pacing capture threshold (PCT) and adjust energy output to deliver a tailored safety margin over the PCT. Abbott AutoCapture™ Algorithm provides beat-by-beat capture confirmation and delivers a high-output backup safety pulse in the event of non-capture. Our objective was to evaluate the longitudinal performance and stability of the Abbott AutoCapture™ algorithm in patients with LBBAP. De-identified remote device data were retrospectively analyzed from consecutive patients in our hospital who received AutoCapture enabled Abbott pacemakers with LBBAP from June 2021 to August 2023. Device stored AutoCapture PCT measurements were then evaluated incrementally over an approximate 2-year period, to evaluate longer-term trends and performance, and also compared with the in-clinic manual PCT. A total of 619 patients with either single chamber (n = 89) or dual-chamber Abbott devices (n = 530) were identified. AutoCapture and manually measured PCTs in-clinic were within 0.25 V in 600/615 (97.6

BACKGROUND:In a first-in-human acute "pass-pull" study, we previously demonstrated that a novel leadless pacemaker (LP) for conduction system pacing (CSP) could acutely pace the deep interventricular septum (IVS). OBJECTIVE:This study aimed to evaluate the safety and efficacy of chronically implanted LPCSP. METHODS:In this study, pacemaker-indicated patients received the Aveir-CSP leadless pacemaker (LPCSP) as either a standalone ventricular pacemaker or as a dual-chamber system paired with an atrial LP. Introduced via the right internal jugular vein, the LPCSP was implanted under fluoroscopic and intra-cardiac echocardiography guidance. The primary safety end point was complications at 1-month. Electrical performance (capture threshold at 0.4 ms, R-wave amplitude, impedance) and capture type (left bundle branch pacing [LBBP] vs left ventricular septal pacing [LVSP] vs deep septal pacing [DSP]) were assessed at implant and at 1 month. RESULTS:Among 20 enrolled patients, 1 was withdrawn for challenging anatomy. LPCSP implantation was successful in 18 of 19 patients: 4 ventricular-only and 14 dual-chamber. At implant, capture thresholds, R-wave amplitudes, and impedance were acceptable, and at 1 month, they were 1.3 ± 0.6 V, 13.1 ± 4.0 mV, and 490 ± 72 Ω, respectively. The capture type at implant was LBBP in 9, LVSP in 5, and DSP in 4 patients, but changed in 6 patients by 1-month follow-up. In addition, 3 patients had dislodgements. For dual-chamber implants, implant-to-implant communication was stable through 1-month. The 1-month LPCSP complication-free-rate was 73.7%; 5 patients experienced complications, including internal jugular-access hematoma, LPCSP dislodgements, and dislocation. CONCLUSION:This first-in-human evaluation demonstrated the feasibility of leadless CSP, but improvements in LPCSP stability fixation require further evaluation.

Background Use of implantable cardioverter defibrillator (ICD) leads for left bundle branch area pacing (LBBAP) has relied on adaptation of conventional leads not designed for conduction system pacing (CSP). Objective This study aimed to evaluate the safety and effectiveness of a purpose-built CSP ICD lead designed for implantation within the LBBA. Methods The ASCEND CSP Investigational Device Exemption (IDE) trial is a prospective, multicenter, global, single arm, pivotal trial evaluating the UltiSynq CSP ICD lead (Model LDA1122Q) in patients undergoing de novo ICD or cardiac resynchronization therapy defibrillator (CRT-D) implantation. The primary safety end point was freedom from lead-related serious adverse device effects through 3 months, compared with a pre-specified performance goal of 88%. The primary effectiveness end point was the 3-month composite success rate of acceptable pacing capture threshold and R-wave sensing amplitude, with a performance goal of 80%. Defibrillation testing success was assessed in a pre-specified cohort. Results Among 205 implant attempts, 202 patients (98.5%), had successful lead implantation, with LBBAP criteria met in 99.0%. Among these, LBBP or likely LBBP capture criteria were met in 86.0%. The 3-month major complication-free rate was 97.5% and the primary effectiveness end point was achieved in 94.6%, exceeding both safety and effectiveness performance goals. Defibrillation testing was successful in 100%, with 92.5% defibrillated with a single 20 J shock. Lead electrical performance remained stable through 3 months. Conclusion In this pivotal IDE trial, a dedicated bipolar CSP ICD lead demonstrated high implant success, stable electrical performance, reliable defibrillation efficacy, and favorable short-term safety. Longer-term follow-up is warranted to confirm durability and sustained clinical benefit.

INTRODUCTION:The AVEIR DR pacemaker (Abbott) is a dual-chamber leadless pacemaker (LP) system that includes right atrial and right ventricular helix-fixation LPs (ALP, VLP), with atrioventricular synchrony maintained via wireless communication between the two devices. The initial, multi-center commercial implant experience of the AVEIR DR dual-chamber LP system has yet to be evaluated. METHODS:Patients indicated for dual-chamber pacing after US commercial release were consecutively included. Implant procedural characteristics were evaluated, and electrical parameters were measured during pre-fixation mapping, post-fixation tether mode, after LP release, and before patient discharge. Any acute procedure- or device-related complications within 30 days were noted. RESULTS:Patients were implanted with AVEIR DR per standard practice (N = 175 at 8 centers; 72 ± 11 years; 60% male; 62% sinus node dysfunction, 37% AV block; 83% de novo implants). ALPs were implanted predominantly in the base of the right atrial appendage (82%), VLPs in the mid-to-apical right ventricular septum (94%). Pre-fixation mapping allowed repositioning to be avoided in 95% of ALPs and VLPs. The total procedure duration was 64 ± 33 min, from initial incision to final suture, with a cumulative fluoroscopy duration of 13 ± 8 min. In both LPs, capture thresholds and sensed amplitudes improved significantly before patient discharge (ALP 1.2 ± 1.0 V, 2.1 ± 1.1 mV; VLP 0.8 ± 0.6 V, 9.5 ± 3.8 mV). At 30 days post-implant, 99% of patients were complication-free. CONCLUSION:The initial commercial experience of the helix-fixation, dual-chamber LP system demonstrated safe and efficient implantation with clinically acceptable electrical metrics and minimal acute complications.

Single -chamber ventricular leadless pacemakers (LPs) are well established. A dual-chamber LP system has recently become available with distinct atrial and ventricular devices. Single-chamber atrial pacing with transvenous devices is infrequent due to future upgrade concerns. This multi-center study evaluated the initial real-world use of the atrial LP by itself to treat isolated sinus node dysfunction (SND). SND patients with normal PR interval and AV conduction to be implanted with atrial LPs after commercial US release were consecutively included. Procedural characteristics were evaluated, and electrical parameters were measured during pre-fixation mapping, post-fixation tether mode, after LP release, and before patient discharge. Acute, 30-day procedure- or device-related complications were noted. Aveir AR devices were implanted per standard local practice (N = 75 patients; 3 centers; 72 ± 13 years; 52

AIMS:The aim of RHYTHM-HF is to provide novel insights into the causes and mechanisms of death in near-consecutive patients discharged following a heart failure hospitalization using data from insertable cardiac monitors (ICMs) and autopsy examinations. METHODS:RHYTHM-HF enrolled an unselected, prospective, near-consecutive, observational cohort of 257 patients admitted to hospital with a primary diagnosis of decompensated heart failure over a 2-year period. Potential participants were screened using N-terminal pro-B-type natriuretic peptide and echocardiography. All enrolled participants received a subcutaneously implanted ICM (which provides long-term cardiac rhythm recordings) before hospital discharge. An optional sub-study invited participants to consent prospectively to autopsy in the event of death. Following hospital discharge, there was no physical follow-up, with longitudinal ICM data obtained by remote upload. Participants were followed for up to 4 years. Data permitting determination of the cause, mode and mechanism of death were collected, including ICM-derived terminal cardiac rhythm and pathological findings at autopsy. Rigorous stepwise clinical adjudication processes were employed in the study (step 1 using clinical data alone, step 2 using additional post-mortem data, and step 3 using additional terminal rhythm data). CONCLUSIONS:The RHYTHM-HF study is a contemporary natural history study which investigated causes and mechanisms of death in patients with heart failure. It is the largest study to report terminal rhythm data in patients with heart failure, the largest contemporary prospective autopsy study in heart failure, and the only study to describe the interaction between terminal rhythm and pathological cause of death using modern adjudication standards. We anticipate new mechanistic insights into the cause and mode of death in heart failure. These findings will generate hypotheses for future clinical research into reducing death in heart failure.

ABSTRACT Background A dual‐chamber leadless pacemaker (LP) system has been developed, employing distinct atrial leadless pacemaker (ALP) and ventricular leadless pacemaker (VLP) devices that maintain atrioventricular synchrony via wireless implant‐to‐implant (i2i) communication with each beat. A new i2i communication‐free programming option was introduced to extend battery longevity and minimize unnecessary ventricular pacing by providing rate‐modulated atrial pacing with backup ventricular pacing when needed (AAI(R) + VVI). The clinical safety and longevity improvement have not been evaluated commercially. Methods Patients indicated for dual‐chamber pacing with new or existing dual‐chamber LP implants were enrolled in this prospective, nonblinded, interventional study. Device diagnostics and battery longevity were interrogated before and after 6 months (6 M) of AAI(R) + VVI programming, with any programming‐related complications or symptoms noted. Total ALP and VLP longevities were compared for DDD(R) at enrollment versus AAI(R) + VVI at 6 M. Results Dual‐chamber LP systems in 139 patients at six centers were evaluated (76 ± 11 years; 53% male; PR 210 ± 56 ms; 80% sinus node dysfunction, 16% AV block of any degree), including 16% new and 84% existing implants (enrolled 7.9 ± 7.5 months postimplant). The 84 patients completing the study ( n = 55 did not return) demonstrated a complication‐free rate of 100.0% and a symptom‐free rate of 97.6% ( n = 2; fatigue, dizziness, shortness of breath). In the 32 patients enrolled with existing implants already in DDD(R) mode who also completed the 6 M visit, AAI(R) + VVI extended the longevities of ALPs by 93% (5.8 ± 1.1 to 11.1 ± 2.7 years, p < 0.001) and VLPs by 61% (10.9 ± 2.1 to 16.9 ± 1.2 years, p < 0.001). Conclusion Clinical use of AAI(R) + VVI programming in dual‐chamber LPs over 6 M resulted in no complications, minimal symptoms, and significantly extended ALP and VLP battery longevities.

BACKGROUND:Leadless pacemakers have transformed pacing by reducing risk for infection and lead-related complications. The feasibility of achieving leadless Bachmann's bundle area pacing (BBAP) for atrial resynchronization is not known. FIRST-IN-HUMAN SUMMARY:A 49-year-old woman with sinus node dysfunction and interatrial conduction delay underwent leadless atrial pacemaker targeting Bachmann's bundle (BB). Using intracardiac echocardiography and electrographic mapping, the pacemaker was positioned at the BB region. Reduced right atrium-to-lateral left atrium conduction time and paced P wave duration were confirmed. DISCUSSION:Right atrial appendage pacing may exacerbate interatrial conduction delay and promote atrial fibrillation. BBAP using a leadless atrial pacemaker, in contrast, has been shown to enhance atrial synchrony. NOVELTY:This case demonstrates the first-in-human permanent implantation of a leadless pacemaker in the BB area, providing a strategy for leadless atrial resynchronization. TAKE-HOME MESSAGE:Leadless BBAP may offer a physiological approach to atrial conduction system pacing by improving atrioventricular dromotropy and reducing subsequent risk for atrial fibrillation.