Solutions to the Challenges of Conduction System Pacing

Recruiting

• Conditions: Conduction System Pacing; Pacing Therapy

• Registration Number: NCT07009834
• Lead Sponsor: Imperial College London

Brief Summary

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, I 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.

Detailed Description

Study A:

100 patients will be prospectively recruited. These patients will be further divided into a derivation and validation group. The derivation group will consist of the first fifty patients recruited (patients 1-50) and the validation group will consist the second fifty patients recruited (patients 51-100).

All 100 patients will have an indication for pacemaker insertion and will undergo a conduction system pacemaker implant.

The derivation group will undergo the research protocol which will include additional measurements from:

1. Ultra-high frequency ECG. A non-invasive surface ECG that detects, isolates and amplifies high frequency components that are filtered out in conventional ECGs.

2. Electro-anatomical mapping. In majority of participants, the invasive mapping catheter will be inserted from the same venous access point to collect detailed electrical and anatomical data. In a small subset of 15 patients, activation maps of the left ventricle will be collected, where the access will be through the femoral artery in the groin.

Non invasive mapping will also be performed in a subgroup of patients with ECGi, where the participants will wear a 252 electrode ECG vest during the procedure. These patients will undergo a pre-procedural CT scan with the vest.

3. Echocardiography. Participants will undergo either transthoracic echocardiography, transoesophageal echocardiography or intracardiac echocardiography.

Additional venous access from the femoral vein in the groin will be sought for patients undergoing intracardiac echocardiography.

4. Haemodynamic assessment Invasive blood pressure will be obtained in patients who already have arterial access for the left ventricular electro- anatomical maps. The sheath will be connected to the pressure inducer. Non invasive beat-by-beat blood pressure will be obtained by a high precision finger cuff (finometer).

A further 50 patients will be prospectively recruited that will make up the validation cohort for Study A. These patients will undergo a conduction system pacemaker as standard clinical practice. The step-by-step algorithm will be prospectively derived from the above to implant the conduction system lead using standard equipment alone; fluoroscopy, PSA and 12-lead ECG. The success rate, conduction system capture threshold, procedure time and fluoroscopy time will be assessed. Although all operators will be highly experienced device implanters, these implants will include operators who are new to conduction system lead implantation.

Study B:

In patients 1-50 undergoing implantation of conduction system pacemakers, 2-lead surface ECG alongside conventional lead data will be collected. A surface 12-lead ECG will be collected as well. The patients will undergo the standard pacing manoeuvres for conduction system pacing. The patient will be paced using the PSA and a 12-lead ECG and 2-lead ECG will be collected via Bard, a computer software that is able to collect highly accurate ECG traces of the heart using mapping catheters placed inside the heart and the surface ECG.

Prospective data from 200 patients with a chronic conduction system lead implant under device follow-up to obtain EGM, 12 -lead ECG and the 2-lead ECG recordings of multiple pacing and sensing configurations will also be collected. These patients will be attending for routine appointments. The pacing and sensing configurations are undertaken as part of routine checks

Study Timeline

• Study Start: 2023-11-06
• Status Verified: 2025-05
• Study First Submitted: 2025-05-07
• Study First Submitted QC: 2025-05-29
• Last Update Submitted: 2025-05-29
• Study First Posted: 2025-06-08
• Last Update Posted: 2025-06-08
• Primary Completion: 2026-11-06
• Study Completion: 2026-11-06

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 300

Inclusion Criteria

1. Patients with a ventricular pacing indication: high grade atrioventricular block and symptomatic trifasicular, bifasicular block or left bundle branch block LBBB for cardiac resynchronisation therapy
2. Adults willing to take part (ages 18 - 100 years old)
3. Able to give consent.

Exclusion Criteria

1. Unable to give consent
2. Children age < 18 years and adults > 100 years old
3. Pregnant patients As per standard of care, female patients of child-bearing age will have a urine pregnancy test prior to their procedure.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
A1: Success rates of conduction system lead implant (novel workflow vs conventional methods)	From enrollment until 6 months after recruitment of last patient
B1: The number of patients with morphology change seen during decrementing output threshold test of 2-lead ECG when compared to gold standard 12-lead ECG	From enrollment until 6 months after recruitment of last patient

Secondary Outcome Measures

Name	Time	Method
A2: Assess capture threshold of conduction system pacing from the optimised workflow to that of conventional methods of conduction system implantation	From enrollment until 6 months after recruitment of last patient	Threshold is measured through the device, looking to achieve the minimum energy (in V) required to safely and reliably capture the cardiac tissue target. In this outcome, we will compare the minimum threshold required to achieve capture of conduction system pacing to that of conventional right ventricular pacing and asses if this the same, higher or lower.
A2: Define left bundle area capture diagnostics and delineate differences between left ventricular septal pacing.	From enrollment until 6 months after recruitment of last patient
B2: Improvement in device battery life measured in days and months with novel device algorithm applied	From enrollment until 6 months after recruitment of last patient	Device battery time is given upon device interrogation and is dependent on percentage of the time the patient is paced and the energy delivered. Battery life will increase if less energy is required. We will assess if there is a increase in days or months in the battery life of the pacemaker with introduction of the novel algorithm.
A2: Procedure and fluoroscopy times of the streamlined workflow to current conventional methods of His-bundle and Left-bundle pacing	From enrolment to until completion of PPM insertion of the last patient recruited into Study A (patient 100); average total of 3 years
A2: Procedure and fluoroscopy times of the streamlined workflow of conduction system implant to current right ventricular pacing	From enrolment to until completion of PPM insertion of the last patient recruited into Study A (patient 100); average total of 3 years

Trial Locations

Locations (1)

Imperial College Healthcare Trust; Hammersmith Hospital; 🇬🇧 London, United Kingdom