Substrate Remodelling and Targeted Ablation in AF

Not Applicable

Recruiting

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

• Registration Number: NCT07047235
• Lead Sponsor: Barts & The London NHS Trust

Brief 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.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2025-06-24
• Study First Submitted QC: 2025-06-24
• Study First Posted: 2025-07-02
• Status Verified: 2025-11
• Study Start: 2025-11-07
• Last Update Submitted: 2025-11-17
• Last Update Posted: 2025-11-18
• Primary Completion: 2029-11-18
• Study Completion: 2030-08-18

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 160

Inclusion Criteria

• Able and willing to provide written informed consent
• Age: 18 years or older
• Clinical diagnosis: Persistent atrial fibrillation
• Treatment status: Scheduled to undergo first-time catheter ablation for persistent AF

Exclusion Criteria

• Inability or unwillingness to provide informed consent
• Under 18 years of age
• Previous left atrial ablation for AF or other atrial arrhythmias
• Any clinical contraindications to undergoing AF catheter ablation

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Assessment of Electrical, Structural and Autonomic Remodelling in Persistent Atrial Fibrillation	4 years	A primary objective of this study is to delineate the remodelling changes that occur in persistent atrial fibrillation and to utilise these to develop tailored ablation strategies.
Establish a Predictive Model to Idenitfy Which Patients are Responders to Pulmonary Vein Isolation Alone and Who Will Require Further Tailored Ablation Strategies	24 months	Based on clinical data approximately only 50% of patients with persistent atrial fibrillation who undergo pulmonary vein isolation remain in sinus rhythm. A main aim of the study is to develop a method to identify which patients will respond to pulmonary vein isolation alone and who will require further tailored ablation strategies.
To Assess if Ablation of Rate Dependent Conduction Velocity Slowing Sites Improves Freedom from Atrial Fibrillation	5 years	All patients who recur after their initial ablation will be invited to undergo a repeat ablation procedure. All patients will undergo ganglionic plexi ablation and reisolation their pulmonary veins. Those who have low voltage zones of more than 30% of their total left atrium will undergo further ablation of rate dependent conduction velocity slowing sites.

Secondary Outcome Measures

Name	Time	Method
Develop Personalised Electrical Atrial Models	5 years	The data taken from the electrophysiological procedures will be used to create mathematical computer models that can be used as an environment to test electrophysiological theories and response to ablation.

Trial Locations

Locations (1)

St Bartholomew's Hospital; 🇬🇧 London, United Kingdom