Catheter Ablation for Atrial Fibrillation

(AWARE Trial)

Recruiting at 10 trial locations

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Ottawa Heart Institute Research Corporation

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 4

Duration: 1 day

411 Participants Needed

Trial Summary

What is the purpose of this trial?

Atrial fibrillation (AF) is an abnormal heart rhythm in which the top chambers of the heart beat very fast. AF catheter ablation is a known technique to convert heart rhythm from AF to normal rhythm. The technique sends out electrical energy through a catheter (long thin round solid tubes) to destroy the heart tissues in a focused area where AF is starting. This technique is practiced at many hospitals, including the Heart Institute, and is not experimental. The AWARE study will compare two techniques of AF catheter ablation: 1. Ablation of tissues in wide circular bands around the opening of the pulmonary veins (bring blood back from lungs) in the left upper chamber of the heart. A medicine called adenosine will be given to unmask any incompletely ablated area. Additional ablations will be given if required. This is standard procedure. 2. Same as above but adenosine will not be used. Instead, additional ablation of a second circular band of tissues around the opening of the pulmonary veins will be given. This additional ablation is not standard procedure and is considered experimental. The Investigators are testing if adding more ablation sites will help maintain normal heart rhythm and reduce the rate of return to AF. The study will compare the occurrence of medical events and complications between the two groups. Identical supplies and equipment used in both techniques have been approved by Health Canada. Adenosine is currently approved by Health Canada for the treatment and diagnosis of arrhythmias. 396 participants from study sites across Canada will be randomly assigned "similar to flipping a coin" to treatment group 1 or group 2. After the ablation, participants will have study follow-up at 3, 6 and 12 months. All participant's will be followed for a minimum of 12 months.

Will I have to stop taking my current medications?

The trial protocol does not specify if you need to stop taking your current medications. However, since participants must have AF that is not controlled by certain medications or cannot tolerate them, you might need to discuss your current medications with the study team.

What data supports the effectiveness of the treatment Augmented-wide area circumferential ablation procedure for atrial fibrillation?

Research shows that circumferential radiofrequency ablation around the pulmonary veins is a promising approach for treating atrial fibrillation, as it targets the areas responsible for irregular heartbeats. Studies have found that combining this with additional ablation strategies can improve outcomes for patients with persistent atrial fibrillation. ^{1 2 3 4 5}

Is catheter ablation for atrial fibrillation safe?

Catheter ablation for atrial fibrillation is generally considered safe, but it can have complications like bleeding and blood clots. Studies show that while it is a common treatment, there are still concerns about the frequency and severity of these complications. ^{5 6 7 8 9}

How is the augmented-wide area circumferential ablation treatment for atrial fibrillation different from other treatments?

The augmented-wide area circumferential ablation treatment for atrial fibrillation is unique because it involves creating a wide area of scar tissue around the pulmonary veins in the heart to prevent erratic electrical signals, which is different from other methods that may focus on isolating specific veins or using different techniques to control heart rhythm. ^{1 3 4 10 11}

Research Team

Girish Nair, MD

Principal Investigator

Ottawa Heart Institute Research Corporation

Eligibility Criteria

This trial is for adults over 18 with symptomatic Paroxysmal Atrial Fibrillation (AF) that's not responding to certain medications, or those who can't tolerate or prefer not to use these drugs. Participants must have had at least one AF episode confirmed by ECG and be able to consent. It excludes individuals with reversible causes of AF, significant heart valve disease, known clots in the heart, pregnancy, adverse reactions to adenosine, persistent/permanent AF, previous ablations for AF or those who can't take blood thinners.

Inclusion Criteria

At least one episode of AF documented on 12-lead ECG, Holter monitor or Loop recorder.

I am 18 years old or older.

I have AFib that doesn't respond to or can't take certain heart rhythm medicines.

Exclusion Criteria

You have had a bad reaction to adenosine in the past.

Subjects that are pregnant

I cannot take blood thinners due to a bad reaction or other reasons.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants undergo wide area circumferential catheter ablation (WACA) with or without augmented ablation lesions

1 day

1 visit (in-person)

Blinding Period

Atrial tachyarrhythmias occurring during this period will be documented but not considered treatment failures

12 weeks

Follow-up

Participants are monitored for safety and effectiveness after treatment with follow-up visits at 3, 6, and 12 months

12 months

3 visits (in-person)

Treatment Details

Interventions

• Augmented-wide area circumferential ablation procedure
• Wide area circumferential catheter ablation

Trial Overview The study compares two catheter ablation techniques for treating abnormal heart rhythm due to AF: standard wide area circumferential ablation using adenosine and an experimental approach adding extra ablation without adenosine. The goal is to see if more ablation reduces recurrence of AF. Participants are randomly assigned into two groups and followed up at 3, 6 and 12 months post-procedure.

Participant Groups

Group I: Augmented- WACA Experimental Treatment 1 Intervention

Augmented- wide area circumferential catheter ablation for atrial fibrillation

Group II: WACA Active Control 1 Intervention

Wide area circumferential catheter ablation procedure for atrial fibrillation

Who Is Running the Clinical Trial?

Ottawa Heart Institute Research Corporation

Lead Sponsor

Trials

200

Recruited

95,800+

Findings from Research

In a study of 33 patients undergoing catheter ablation for atrial fibrillation, significant reductions in left atrial (LA) size and function were observed, with LA volume decreasing by 15% and ejection fraction by 14% after the procedure.

The decrease in LA function was strongly correlated with the volume of scar tissue in the LA, suggesting that the extent of radiofrequency ablation may impact post-procedural risks, including thromboembolic events.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Left atrial function and scar after catheter ablation of atrial fibrillation. Wylie, JV., Peters, DC., Essebag, V., et al.[2016]

In a study of 2,323 patients undergoing catheter ablation for atrial fibrillation, major complications occurred in 4.0% of cases, with vascular access complications being the most common.

Female patients and those with longer procedure times were found to have a higher risk of complications, indicating that these factors should be considered when assessing patient safety during catheter ablation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Updated national multicenter registry on procedural safety of catheter ablation for atrial fibrillation. Bertaglia, E., Stabile, G., Pappone, A., et al.[2014]

Catheter ablation is a standard and effective treatment for rhythm control in patients with atrial fibrillation (AF), helping to restore normal heart rhythm.

The review covers the latest techniques and technologies used in AF catheter ablation, including different energy forms and procedural methods, ensuring comprehensive understanding for optimal patient outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Catheter ablation of atrial fibrillation : Status quo]. Jilek, C., Lewalter, T.[2020]

References

1. United States pubmed.ncbi.nlm.nih.gov

Atrial electroanatomic remodeling after circumferential radiofrequency pulmonary vein ablation: efficacy of an anatomic approach in a large cohort of patients with atrial fibrillation. [2022]

2. Germany pubmed.ncbi.nlm.nih.gov

Catheter ablation of persistent atrial fibrillation : Long-term results of circumferential pulmonary vein ablation in combination with a linear lesion at the roof of the left atrium. [2019]

3. United States pubmed.ncbi.nlm.nih.gov

Effects of circumferential ostial radiofrequency lesions on pulmonary vein activation recorded with a multipolar basket catheter. [2006]

4. United States pubmed.ncbi.nlm.nih.gov

Left atrial function and scar after catheter ablation of atrial fibrillation. [2016]

5. England pubmed.ncbi.nlm.nih.gov

Safety and efficacy of multipolar pulmonary vein ablation catheter vs. irrigated radiofrequency ablation for paroxysmal atrial fibrillation: a randomized multicentre trial. [2022]

6. United States pubmed.ncbi.nlm.nih.gov

Complications of atrial fibrillation ablation in a high-volume center in 1,000 procedures: still cause for concern? [2022]

7. Netherlands pubmed.ncbi.nlm.nih.gov

Dabigatran versus warfarin anticoagulation before and after catheter ablation for the treatment of atrial fibrillation. [2021]

8. United States pubmed.ncbi.nlm.nih.gov

Updated national multicenter registry on procedural safety of catheter ablation for atrial fibrillation. [2014]

9. United States pubmed.ncbi.nlm.nih.gov

Left atrial contractility is preserved after successful circumferential pulmonary vein ablation in patients with atrial fibrillation. [2022]

10. Netherlands pubmed.ncbi.nlm.nih.gov

A novel method for localization and ablation of conduction gaps after wide antral circumferential ablation of pulmonary veins. [2018]

11. Germany pubmed.ncbi.nlm.nih.gov

[Catheter ablation of atrial fibrillation : Status quo]. [2020]