Conduction System Pacing

The present study is a prospective, multicenter, non-inferiority, randomized controlled trail. It aims to investigate whether the efficacy of conduction system pacing (CSP) is non-inferior to biventricular pacing (BiVP) in patients with heart failure and right ventricular pacing (RVP) requiring upgrading to cardiac resynchronization therapy (CRT).

The objective of this study is to evaluate the safety and effectiveness of LBBA pacing/sensing in patients implanted with the Tendril STS 2088TC or UltiPace LPA1231 lead through 6 months post-implant.

The implantation of a pacemaker and conventional cardiac pacing from the right ventricle (apex or septum) is an effective and safe therapy for the treatment of patients with atrioventricular block and bradycardia.

The NORDIC-CSP trial is an investigator-initiated, blinded, nordic RCT aimed at evaluating whether using direct pacing of the HIS bundle (HIS)-pacing or left bundle branch (LBB) pacing is superior to conventional biventricular pacing in reducing the incidence of the composite endpoint of death and non-planned HF hospitalization. The study will be conducted in the 4 CRT-centres in Denmark and 6-8 centres from countries Sweden, Norway and Finland.

Conventional right ventricular pacing (RVP) has been associated with ventricular dyssynchrony and an increased risk of pacing-induced cardiomyopathy, which may lead to worse clinical outcomes. These adverse effects are more pronounced in patients with pre-existing left ventricular dysfunction. To overcome these limitations, left bundle branch area pacing (LBBAP), which directly engages the cardiac conduction system to preserve physiological ventricular activation, has been increasingly adopted in clinical practice. However, in patients with atrioventricular block and preserved left ventricular ejection fraction (LVEF ≥50%), evidence demonstrating the long-term clinical superiority of LBBAP over conventional RVP remains limited. As a result, both pacing strategies continue to be used in current practice. This multicenter randomized trial aims to compare the efficacy, safety, and lead stability of LBBAP using a stylet-driven extendable screw-in lead versus conventional RVP in patients with atrioventricular block and preserved ejection fraction.

A randomized, single-blind study comparing two pacing strategies in patients with atrioventricular block requiring permanent pacemaker implantation. This trial evaluates the impact of conduction system pacing (left bundle branch area pacing) versus standard right ventricular pacing on central hemodynamics, cardiac function, and patient quality of life over 12 months. The study will enroll 124 patients from two Estonian tertiary hospitals and measure central systolic arterial pressure as the primary outcome, with secondary assessments of arterial stiffness, echocardiographic parameters, electrical activation patterns, and quality of life scores.

This prospective observational study evaluates the burden of Atrial High-Rate Episodes (AHRE) in patients without a prior history of atrial fibrillation who undergo concurrent Bachmann Bundle Area Pacing (BBAP) and Left Bundle Branch Pacing (LBBP). Physiological pacing at these sites aims to improve interatrial conduction and reduce the risk of atrial arrhythmias. The study includes a comparative assessment across three patient groups: 1. BBAP + LBBP (physiological pacing group) 2. Right Atrial Appendage (RAA) pacing + LBBP 3. Conventional pacing - RAA and Right Ventricular (RV) pacing AHRE burden will be quantified via device diagnostics and remote monitoring at 3, 12 and 24 months post-implantation. Episodes will be classified by duration (0-6 min, 6-24 h, \>24 h), differentiating subclinical AHRE from clinically documented AF. Secondary analyses include electrocardiographic changes (P-wave indices), the need for antiarrhythmic therapy, and comprehensive echocardiographic evaluation of atrial function (e.g., LA strain, conduction delays, LAVI). The study aims to determine whether physiological pacing (BBAP + LBBP) provides superior protection against AHRE development compared with RAA + LBBP and conventional pacing strategies.

Conduction system pacing is a new way of stimulating the heart using pacemaker wires. Traditional pacemakers stimulate the heart muscle which causes disordered heart beats: the walls of the heart move at different times. This wears down the heart over time. Conduction system pacemakers stimulate the heart's electrical system directly producing natural heart beats that are much less disordered. These pacemakers can be challenging to insert with different heart shapes, sizes and scars. This can increase procedure times and time exposed to xray as pacemakers are inserted using x-rays to guide where the lead is implanted. This study aims to allow conduction system pacemakers to be implanted without the use of normal xray (fluoroscopy). The investigators will create an anatomical shell of the heart using special plastic (mapping) catheters that is inserted within the heart from the groin. The investigators will use a special heart scanning (echo) catheter to see how the pacemaker wire is inserted into the heart muscle. The investigators will use MRI to confirm that the information we collect is accurate. Using this information the investigators will create a protocol to implant a lead that does not require xray, using only the mapping catheter.

Conduction system pacing is a new way of stimulating the heart using pacemaker wires. Traditional pacemakers stimulate the heart muscle which causes disordered heart beats: the walls of the heart move at different times. This wears down the heart over time. Conduction system pacemakers stimulate the heart's electrical system directly producing natural heart beats that are much less disordered. Unfortunately, these pacemakers can only be implanted by a small group of experts at specialised centres with specialist equipment. This study aims to allow conduction system pacemakers to be offered to any patient at any hospital by simplifying the process of inserting the pacemaker wires and the improving the pacemaker's ability to interpret electrical traces. Firstly, the best locations in the heart for conduction system pacemaker wires using specialised electrical traces, MRI and ultrasound scans will be identified. Features that can be seen on X-ray to guide doctors to these locations will then be identified. Secondly, the investigators will collect electrical information from the pacemaker wires and additional electrical traces to develop an algorithm that can make the interpretation the electrical traces more accurate.

This prospective multicenter registry will evaluate the long-term electrical, echocardiographic, and clinical outcomes of conduction system pacing (CSP). There is currently limited data in the literature regarding the long-term results and benefits of CSP. The long-term maintenance of conduction system (His bundle or Left Bundle Branch) capture and physiological ventricular activation is an essential prerequisite for the expected benefits of this technique. There is currently no prospective study evaluating the preservation of CSP during long-term follow-up. The design of the present study will allow reliable evaluation of CSP maintenance at 2 years follow-up. The prospective collection of electrical data (pacing thresholds, impedance, R wave sensing) during pacemaker follow-up visits will confirm thresholds stability over the long term. The incidence of atrial fibrillation episodes will also be precisely evaluated and will provide new information. Although pathophysiological studies have demonstrated less impairment of left atrial function with conduction system pacing, there is currently no data on the incidence of atrial fibrillation in patients implanted with a CSP pacemaker. Echocardiographic data will be prospectively collected in order to analyse the evolution of left ventricular ejection fraction (LVEF) after CSP. This systematic follow-up is rarely found in CSP studies, often retrospective, with significant missing echocardiographic data. The hypothesis is that patients benefiting from CSP will not develop the deleterious effects demonstrated with conventional right ventricular pacing, such as left ventricular dilation and LVEF impairment. Inter- and intraventricular asynchrony criteria will also be systematically evaluated during follow-up echocardiography.Finally, this prospective cohort will also systematically collect clinical follow-up data (hospitalizations for heart failure and NYHA stage).