Substrate Remodelling and Targeted Ablation in AF

Summary

Atrial fibrillation (AF) is the most common heart rhythm disorder, affecting millions worldwide and causing symptoms such as palpitations, fatigue and breathlessness. It also increases the risk of stroke and heart failure, so effective treatment is essential.

A treatment for AF involves catheter ablation, a minimally invasive procedure where problematic areas of the heart are targeted using controlled energy. This is done by passing wires called catheters, through blood vessels at the top of the leg all the way to the heart. However, this isn't effective for everyone and approximately half of patients experience a return of AF despite treatment.

In this researcher-led study at St Bartholomew's Hospital , the investigators will use a method called electroanatomical mapping to make a 3D picture of the left atrium, the heart's upper left chamber. To make this picture more detailed, information will be collected - such as how strong electrical signals are (voltage), how fast and in which direction they travel through the heart to describe abnormal areas and areas of scar within the heart. Information will also be gathered about the routes electricity takes and the nerve activity in the heart muscle. These detailed maps will help to understand why AF can continue indefinitely in some people, why ablation works for some people and not others, and improve how ablations are done to make them more effective.

All participants will undergo catheter ablation with these mapping methods integrated into the procedure. If AF recurs, patients will be invited for a second ablation targeting specific abnormal areas depending on the amount of scar found. This will be standardised across patients.

Patients will be followed for 12 months, with structured visits at 3, 6, 9 and 12 months and 48-hour ECG recorders at 6 and 12 months. By tracking how the heart's structure and electrical behaviour evolve, the aim is to to see if map-guided ablation reduces the need for further procedures, lowers healthcare costs and improves quality of life.

Ultimately, this study will provide clear, reproducible insights into AF mechanisms and yield practical guidance so clinicians can predict who will benefit from standard ablation treatment and who may require extra, map-guided treatment.

Conditions

• Atrial Fibrillation (AF)
• Atrial Fibrillation Mechanisms
• Catheter Ablation
• Low Voltage Areas

Interventions

PROCEDURE

Pulmonary vein reisolation

The pulmonary veins will be checked electrically and further ablation will be undertaken if they are not isolated.

PROCEDURE

Ganglionic plexi ablation

Sites where ganglionix plexi have been found will be ablated.

PROCEDURE

Substrate ablation

Areas of rate dependent conduction velocity slowing will be targeted using cathether ablation

Sponsors & Collaborators

• Barts & The London NHS Trust

  lead OTHER

Study Design

Allocation

NON_RANDOMIZED

Purpose

OTHER

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-11-07

Primary Completion

2029-11-18

Completion

2030-08-18

Countries

• United Kingdom

Study Locations