Comparing Three Types of Specialist Pacemakers to Improve Heart Function and Reduce Rhythm Problems in Heart Failure

Summary

The goal of this clinical trial is to find out which type of specialist pacemaker-known as cardiac resynchronisation therapy (CRT)-works best for people with heart failure and a delay in how the lower chambers of the heart beat together (called electrical dyssynchrony).

The main aims of the study are:

To compare the effects of conventional biventricular pacing (BVP), conduction system pacing (CSP) and left-bundle optimised CRT (LOT-CRT) on heart failure symptoms and heart rhythm problems over six months.

To explore how these pacing methods affect heart muscle strength, electrical activity, and overall heart function.

Participants will:

Attend four hospital visits over a six-month period.

At Visit 1, meet a member of the research team to discuss the study and have screening tests to check eligibility. Participants will also have a smartphone app installed and receive training on how to record their daily heart failure symptoms.

At Visit 2, have a CRT pacemaker implanted. The type of pacemaker will be chosen at random, with a 1 in 3 chance of receiving:

* Biventricular pacing (BVP); the current standard treatment
* Conduction system pacing (CSP)
* LOT-CRT (Left-bundle optimised CRT); a combination of both

At Visit 3 (around 12 weeks after implantation) and Visit 4 (6 months after implantation), take part in routine follow-up assessments to check the pacemaker and heart function.

At Visits 2 and 4, also undergo non-invasive electrical mapping tests, including wearing a specialised vest and having a low-dose CT scan of the chest. These tests help researchers understand how the heart's electrical system responds to different pacing methods.

Conditions

• Heart Failure and Reduced Ejection Fraction
• Dyssynchrony

Interventions

DEVICE

Biventricular pacing

Cardiac resynchronisation therapy with one lead to right ventricular endocardium and one lead to left ventricular epicardium, accessed via the coronary sinus.

DEVICE

Conduction system pacing

Cardiac resynchronisation therapy with single lead targeting direct capture of the conduction system. Primary target should be left bundle area, with backup target of His bundle. If direct capture of the conduction system cannot be achieved by conventional clinical criteria, left septal pacing targeted at the left bundle branch area will be accepted.

DEVICE

Left bundle optimised cardiac resynchronisation therapy

Cardiac resynchronisation therapy delivered by conduction system optimised hybrid configurations. Primary configuration should be conduction system pacing lead targeted at the left bundle area combined with left ventricular epicardial lead accessed via the coronary sinus (LOT-CRT). Backup configuration of conduction system pacing lead targeted at the His bundle combined with left ventricular epicardial lead accessed via the coronary sinus (HOT-CRT).

Sponsors & Collaborators

• Imperial College Healthcare NHS Trust

  collaborator OTHER

• Imperial College London

  lead OTHER

Principal Investigators

• Zachary I Whinnett, MBBS, BMedSci, MRCP, PhD · Imperial College London

• Ahran D Arnold, MBBS, BSc, MSc, MRCP, PhD · Imperial College London

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-11-12

Primary Completion

2028-10-24

Completion

2028-10-24

Countries

• United Kingdom

Study Locations