Substrate Guided Ablation Therapy for Atrial Fibrillation

• Conditions: Persistent Atrial Fibrillation
• Interventions: Procedure: Substrate guided left atrial ablation

• Registration Number: NCT04657978
• Lead Sponsor: Royal Brompton & Harefield NHS Foundation Trust

Brief Summary

Atrial fibrillation (AF), often referred to as an 'irregular heartbeat', is the most common abnormal heart rhythm worldwide. AF may be intermittent (termed paroxysmal) or sustained (termed persistent).Catheter ablation is increasingly being used to manage individuals with AF, however in a significant proportion of cases AF recurs. Such rhythm control interventions are known to be less effective in individuals with persistent AF compared with those with paroxysmal AF. Analysis of heart tissue of individuals with AF show deposition of scar tissue within the heart muscle and this scar tissue promotes abnormal electrical activity that is involved in causing AF. The aim of the proposed study is to evaluate the feasibility and effectiveness of combining conventional pulmonary vein isolation (PVI) during catheter ablation for AF with adjunctive substrate ablation.

Detailed Description

This is a single-centre, non-randomized study investigating the feasibility, safety and efficacy of substrate guided ablation in persistent AF.

The study population will be patients between the ages of 18 and 80 with symptomatic, persistent atrial fibrillation (≥1 year) referred for catheter ablation on standard clinical grounds.

The catheter ablation procedure will be performed using the Precision Ensite™ three dimensional mapping system and the Advisor High Density Grid™ mapping catheter (Abbott Medical Incorporated). All patients will undergo conventional pulmonary vein isolation (PVI). As an adjunctive strategy to PVI, low voltage areas (used as a surrogate for atrial scar), as derived from the voltage map, will be targeted for ablation in order to isolate or homogenise these areas of the atrium. A pre-procedural cardiac magnetic resonance imaging scan will be performed in all patients.

All patients will undergo 12 months follow-up with an ECG and ambulatory holter monitoring at 3, 6 and 12 months.

Study Timeline

• Study First Submitted: 2020-11-27
• Status Verified: 2020-12
• Study First Submitted QC: 2020-12-06
• Last Update Submitted: 2020-12-06
• Study First Posted: 2020-12-08
• Last Update Posted: 2020-12-08
• Study Start: 2021-01
• Primary Completion: 2022-09
• Study Completion: 2023-01

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

• Patients aged ≥18 years and ≤ 80 with a clinical indication for persistent atrial fibrillation ablation

Exclusion Criteria

• Contraindication to anticoagulation
• Thrombus in the left atrium despite anticoagulation
• Cerebrovascular accident within the previous 6 months
• Patients actively participating in another research study will be not be permitted to enrol. Patients who have been involved with other research studies will be able to participate after a minimum period of 3 months after completion of prior study follow up
• Females of childbearing potential must have a negative pregnancy test on the day of the ablation procedure due to the radiation exposure during the procedure

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Substrate guided intervention arm	Substrate guided left atrial ablation	Participants recruited to the study will undergo High Density Wave Solution™ guided substrate mapping of the left atrium. Ablation will thereafter be performed to comprise wide area circumferential ablation of the pulmonary veins in pairs, followed by ablation of low voltage zones in the left atrium.

Primary Outcome Measures

Name	Time	Method
Freedom from atrial arrhythmias (>30 seconds) after a single procedure without anti-arrhythmic drugs (AADs) within 12 months, measured by ambulatory holter monitoring	12 month	All participants will have an ECG and ambulatory holter monitor performed at 3, 6 and 12 months after the procedure.

Secondary Outcome Measures

Name	Time	Method
To compare 1-year arrhythmia free clinical outcome with historical control patients matched by propensity score	12 Months	Freedom from AF defined as no documented AF (\>30 seconds) following the 3 months blanking period following a single procedure, off anti-arrhythmic drugs.
Safety endpoint evaluating the incidence of intraprocedural (primarily Advisor High Density Grid™ mapping catheter) related adverse events	12 Months
To correlate cardiac MRI derived scar distribution and burden in the left atrium with the baseline voltage map obtained using the Advisor High Density Grid™ catheter	12 Months	The left atrium will be segregated into pre-defined regions and marked for presence or absence of fibrosis as identified on MRI scans and low voltage identified on invasive mapping. Inter-class correlation will performed to evaluate consistency between modalities.