Pacing-Induced Cardiomyopathy

Atrioventricular node ablation with permanent pacing (the "pace-and-ablate" strategy) controls ventricular rate in atrial fibrillation that has not responded to drug therapy or catheter ablation. Chronic right ventricular pacing, however, can cause pacing-induced cardiomyopathy (PICM), and it is not well established which patients are at risk and should therefore receive conduction system pacing or biventricular pacing instead. REPACE is a multicentre retrospective cohort of consecutive patients who underwent atrioventricular node ablation from January 2011 onwards at five centres in Switzerland, the United Kingdom and Poland: Liverpool Heart and Chest Hospital, Inselspital Bern, University Hospital Basel, Geneva University Hospitals and the Silesian Centre for Heart Diseases, Zabrze. More than 2,000 patients ablated up to March 2024 have been included to date; patients ablated after that date at the participating centres are being added. The study has three aims: to validate, in an independent multicentre population, a previously published risk model for pacing-induced cardiomyopathy; to describe the procedural technique and outcomes of atrioventricular node ablation across different health systems; and to estimate the health-economic impact of the pace-and-ablate strategy. Pacing-induced cardiomyopathy is defined as an absolute reduction in left ventricular ejection fraction of at least 10 percentage points to a value below 50%. All potential endpoints are adjudicated by a clinical events committee blinded to the classification made at the site.

The PACEVALUE study is a large, international observational study aiming to improve the treatment of patients receiving cardiac implantable electronic devices (CIEDs) such as pacemakers, implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices. While these devices are vital for managing heart rhythm disorders and heart failure, chronic right ventricular pacing can sometimes cause a condition called pacing-induced cardiomyopathy (PICM), where the left side of the heart weakens over time, leading to increased hospitalizations and higher mortality. The main goal of the study is to develop and validate a risk prediction model using routine clinical and device data to identify patients at highest risk of PICM before device implantation. By stratifying patients according to this risk score, the study aims to guide personalized pacing strategies, including conduction system pacing (CSP) and CRT options, to improve outcomes and reduce complications. The study will include approximately 4,500 patients across centers in Switzerland, Germany, Poland, Croatia, Bulgaria, Cyprus, and Australia, with planned inclusion of sites in the UK. Patients are included in two arms. In the prospective arm, consecutive patients are enrolled at the time of their device procedure. In the retrospective arm, centers include patients they have already treated, using data already recorded during clinical care. Both arms use the same case report form and the same endpoint definitions. Participants are followed annually for up to ten years, with data collection including heart function imaging, device data, clinical outcomes, patient-reported outcomes (PROMs/PREMs), and healthcare costs. This observational study will also compare clinical practices and cost-effectiveness of different pacing strategies across diverse healthcare systems, aiming to inform evidence-based, patient-centered, and economically efficient device therapy decisions. The findings will lay the groundwork for future registry-based randomized controlled trials to further optimize pacing treatments.

Guidelines for patients having first-time implants advocate that even when heart function is only mildly impaired, modern pacing approaches should be utilised to avoid the potentially damaging effects of RV pacing to preventing symptoms from pacing induced or worsened cardiomyopathy. However, once a traditional (RV) pacemaker is implanted, development of impaired heart function does not prompt a device upgrade. Even at the end of battery life, physicians simply replace it like-for-like. This trial tests whether such patients have better symptoms and quality of life if changed to a modern physiological pacing strategy from the traditional RV pacing approach. In this crossover trial, participants will be upgraded to a physiological pacing strategy. After their procedure, they will have a one-month run-in period to recover from the procedure (their pacemaker will be programmed to continued RV pacing). They will be have 2 one-month blinded time periods, randomised to physiological pacing or right ventricular pacing alternately. They will subsequently undergo two six-month blinded randomised time periods. Patients will document symptoms monthly on a mobile phone application or computer. At the end of each time period, they will have measurements of heart function, a walking test and quality-of-life questionnaires including the SF-36 questionnaire. The investigators hypothesise that upgrading to physiological pacing strategies will improve patients' quality of life.

The investigators aim to prospectively test the comparative effectiveness of His or Left bundle branch pacing in relation to patient centered outcomes (quality of life, physical activity, heart failure hospitalization, mortality) and comparative safety in relation to device-related complications and re-interventions (e.g., lead dislodgement, infection) relative to standard of care biventricular pacing in patients with heart failure due to left ventricular systolic dysfunction (LVEF≤50%) and with either a wide QRS (≥130 ms) or with/anticipated \>40% pacing who are already receiving current standard heart failure pharmacological therapy.

Right ventricular pacing causes ventricular dyssynchrony and may be associated with impaired outcome. In the last decade, several approaches for more physiological pacing became available and were implemented in the latest guidelines. However, compared to conventional device implantation, cardiac resynchronization, His bundle pacing and left bundle area pacing remain demanding procedures in the individual case. Goal of the single center observational "Pace conduct" study is to evaluate implantation success, safety and outcome of pacing methods that maintain physiologic ventricular activation.

It is unknown whether left bundle branch area pacing (LBBAP) or biventricular pacing best prevents or reverses left ventricular (LV) adverse remodelling in patients with atrial fibrillation (AF) who require ventricular pacing or CRT. This randomized non-inferiority cross-over trial will compare left ventricular end-systolic volume change and secondary endpoints between LBBAP and biventricular pacing in patients with AF and LV dysfunction.