Substrate Remodelling and Targeted Ablation in AF (STRATA-AF)

Barts & The London NHS Trust

Status: Enrolling

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

Treatments: Procedure: Pulmonary vein reisolation; Procedure: Ganglionic plexi ablation; Procedure: Substrate ablation

Study type: Interventional

Funder types: Other

Identifiers

NCT07047235

407

Details and patient eligibility

About

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.

Enrollment: 160 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Other

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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160 participants in 2 patient groups

Minimal Low Voltage Zones Group

Active Comparator group

Description:

These are patients who've had recurrence of AF after their first ablation and less than 30% of their atria is comprised of low voltage zones. They will undergo autonomic ganglionic plexi site ablation combined with pulmonary vein re-isolation.

Treatment:

Procedure: Ganglionic plexi ablation

Procedure: Pulmonary vein reisolation

Significant Low Voltage Zones Group

Active Comparator group

Description:

These are patients who've had recurrence of AF after their first ablation and greater than 30% of their atria is comprised of low voltage zones. They will undergo targeted ablation of conduction slowing sites in addition to ganlionic plexi site ablation and pulmonary vein reisolation.

Treatment:

Procedure: Substrate ablation

Procedure: Ganglionic plexi ablation

Procedure: Pulmonary vein reisolation