Reversal of Atrial Substrate to Prevent Atrial

Atrial fibrillation (AF) is a major health problem, with a prevalence of 0.4-1% of the population. It results in high healthcare costs and significant morbidity, especially for patients with severe symptoms. Exercise and risk factor modification to prevent and modify AF has garnered a significant amount of support in cohort studies that have proven benefit. It is well known that age, body mass index, valvular heart disease, heart failure, hypertension and sleep apnea are risk factors for AF, most of which are modifiable if targeted appropriately. In addition, catheter ablation techniques have evolved and improved to reduce AF recurrence in those who are most symptomatic, and either have heart failure, or are at risk for its development. Despite these advances, the recurrence of AF remains high.

We propose to determine whether early treatment of the arrhythmogenic substrate, with or without aggressive risk factor modification, is most important in prevention of recurrent AF. It is hypothesized that patients with underlying risk factors that promote AF will benefit most from a combined strategy of aggressive risk factor modification in combination with catheter ablation.

The study design will be a two-arm, parallel group, randomized clinical trial comparing catheter ablation versus catheter ablation plus aggressive risk factor therapy, followed by maintenance with blinded endpoint evaluation. Patients with symptomatic AF and two of the following will be included: BP ≥ 140/90 or history of hypertension, BMI≥27, diabetes, prior stroke/TIA, history of heart failure (prior heart failure admission due to AF or LVEF<40%), age≥65. Patients will be excluded if they are exercising >150 minutes/week by self-report. Patients will be randomly allocated to one of the following groups: 1) AF ablation within 3 months, 2) AF ablation at 3 months, with a 12 week home-based exercise/risk factor management program, followed by maintenance therapy. A 5-month treatment period will be observed to deliver the interventions and have a 2 month blanking period post ablation. Guideline-directed therapy for risk factors will occur in all groups, including BP, cholesterol, diabetes, alcohol reduction and sleep apnea screening. All patients will undergo implantation of an implantable cardiac monitor (ICM) at baseline. The primary outcome will be a composite of clincally significant AF (AF ≥ 24 hours), AF-related hospitalization/emergency department visits 5 months post randomization. Secondary outcomes will include: Death, Stroke or Systemic embolism, Quality of Life, Health Outcomes, recurrent AF, \& AF burden. The minimum sample size required is 500. Safety outcomes include: AF catheter ablation procedural complications, Anti-arrhythmic medication related adverse events, \& Death.