Ablation of Low Voltage Regions in Persistent Atrial Fibrillation

Study Overview
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Brief Summary
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Background. Atrial fibrillation (AF) is a disorganised rhythm of the upper chambers of the heart. It can lead to severe complications including stroke or heart failure. It can be treated with radiofrequency ablation (RFA). This technology works by heating heart muscle inside the heart to break the electrical circuits responsible for the abnormal rhythm. The energy is delivered into the heart with plastic tubes that have metal electrodes, inserted through the groin veins and removed after the procedure. The patient is usually put to sleep during the intervention. If the AF has been present for more than seven days but for less than one year it is called persistent, and it can be difficult to treat successfully with the usual methods. Goals. The study will test a new RFA technique to treat patients with persistent AF. This involves identifying areas within the left upper chamber that have a lower electrical voltage than the surrounding heart muscle and applying RFA to the border zones of these areas. Methods. The new technology combined with the usual procedure will be compared to the usual procedure alone. All patients will receive ablation according to the new technique and results will be compared to a historical control group from the trial institution. Follow up. Patients will be followed up for 12 months with clinic visits and heart rhythm checks. Potential benefit. The new technique will be assessed for success at keeping patients free from persistent AF compared to the usual methods. The study will be performed at Imperial College Healthcare NHS Trust, at the Hammersmith Hospital. Licensed clinical software will be used from St Jude Medical to guide ablation and a special research software module will be used to analyse data from the heart following ablation. The study will be sponsored by Imperial College Healthcare NHS Trust

Official Title
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Catheter ABlation of Low Voltage Regions in the Treatment of Persistent Atrial Fibrillation (ABLOVO-AF Study)

Conditions
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Persistent Atrial Fibrillation

Intervention / Treatment
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* Procedure: Low voltage ablation
* Procedure: Pulmonary Vein Isolation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Suitable candidate for catheter mapping/ablation for arrhythmias. Eighteen (18) to eighty-five (85) years of age Body Mass Index (BMI) < 40 (Wt. in Kgs / Ht. in m2) Signed Informed Consent Exclusion Criteria: Severe cerebrovascular disease Moderate to severe renal impairment (eGFR < 30) Active gastrointestinal bleeding Active infection or fever Short life expectancy Significant anemia Severe uncontrolled systemic hypertension Severe electrolyte imbalance Ejection fraction of < 35% Congestive heart failure (NYHA Class IV) Unstable angina requiring emergent PTCA (percutaneous transluminal coronary angioplasty) or CABG (coronary artery bypass graft) Recent myocardial infarction Bleeding or clotting disorders Uncontrolled diabetes Inability to receive IV or oral Anticoagulants Unable to give informed consent (these patients would not be recruited) Previous catheter or surgical ablation treatment for atrial fibrillation. Paroxysmal atrial fibrillation. Pregnancy (urinary pregnancy test will be offered on the day of the procedure for all women of reproductive age) Drug and/or alcohol abuse Transient factors for AF Severe LA enlargement of >60 mm in diameter on echocardiography Patients who have participated in another study of an investigational medicinal product in the last 3 months.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Pulmonary Vein Isolation<br>Historical control from cases performed in year 2017 at Hammersmith Hospital. Intervention: Pulmonary vein isolation. | Procedure: Pulmonary Vein Isolation<br>* Catheter ablation aiming for the electrical isolation of the pulmonary veins.<br>|
| Experimental: Low voltage ablation<br>Active arm, Intervention: Standard pulmonary vein isolation and Low Voltage Ablation. | Procedure: Low voltage ablation<br>* Catheter ablation of low voltage areas in the left atrium and catheter ablation aiming for the electrical isolation of the pulmonary veins.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Atrial fibrillation recurrence | Recurrence of atrial arrhythmia of at least 30s in duration. Investigation period for arrhythmia recurrence will be between 3 and 12 months after the first procedure, allowing for a blanking period of 3 months. | 3-12 months. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Canadian Cardiovascular Society Severity in Atrial Fibrillation Score | Canadian Cardiovascular Society Severity in Atrial Fibrillation (CCS-SAF) change. 0 represents no symptoms, 4 represents symptoms that significantly interfere with quality of life and exercise capacity. | 12 months | 
| Antiarrhythmic drugs | Change in the number of antiarrhythmic drugs per patient | 3-12 months | 
| Number of AF ablations | Number of additional AF ablations | 3-12 months | 
| Complication rate | Number and rate of complications in the study population. | 3-12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Radiofrequency Catheter Ablation