Characterization of Arrhythmia Substrate to Ablate Persistent Atrial Fibrillation (COAST-AF) Randomized Controlled Trial

Atrial fibrillation (AF) is a major health problem that affects 350,000 Canadians. AF, an abnormal heart rhythm, increases the risk of heart failure, stroke and death. These risks increase when AF worsens to a level known as persistent AF. AF can be treated with catheter ablation, a treatment that aims to restore a normal heart rhythm. When successful AF catheter ablation improves quality of life, and decreases the risk of death or hospitalization for cardiac causes. Yet, only 50-60% of patients with persistent AF who undergo standard of care (pulmonary vein isolation catheter ablation alone) remain AF-free at one year. The optimal strategy for ablation of persistent AF is not yet known. We know that scar tissue in the atria (upper chamber of the heart) leads to AF. Recently, our group's pilot work demonstrated that catheter ablation of scarred regions in the atria in addition to pulmonary vein isolation has revealed promising results. Recent studies using a similar approach support our findings, yet a synthesis of current available research reveals that it is of variable quality with important limitations. To confirm the findings from these studies, experts in the field have called for a larger, more representative study. We are answering this call. We propose COAST-AF, a clinical trial to determine the safety and efficacy of atrial scar ablation in addition to pulmonary vein isolation versus pulmonary vein isolation alone (standard of care). COAST-AF is the only study that can provide a definitive answer to this crucial question in cardiac arrhythmia care. We anticipate this trial will directly impact the treatment of thousands of patients with persistent AF in Canada and Worldwide.