Catheter ablation of the cavotricuspid isthmus (CTI) is an effective and safe procedure in patients with atrial flutter (AFL) with excellent long-term results in preventing AFL recurrences. However, new-onset atrial fibrillation (AF) commonly develops after this procedure and has important clinical implications for patient management. Few studies have assessed the long-term incidence and prevalence of AF after CTI ablation via intensive continuous rhythm monitoring with an implantable cardiac monitor. Furthermore, whether the development of AF can be impacted beneficially by adjunctive therapeutic approaches is not known. The co-primary objectives of this pilot study in patients with typical atrial flutter (AFL) but no previously detected AF are: 1) to accurately determine the long-term incidence of new-onset AF after CTI ablation using an implantable rhythm monitor; 2) to compare the rates of new onset AF in subjects randomized to standard, usual-care, medical therapy following CTI ablation compared with those randomized to treatment with an aldosterone antagonist (spironolactone) in addition to their usual care medications. The patient population will be subjects with typical atrial flutter and a history of hypertension or heart failure, but no known AF episodes, scheduled to undergo catheter ablation of the CTI for treatment of AFL. Patients will be randomized to remain on their standard, usual-care. medications or to take oral spironolactone (a standard, FDA-approved medication used in the treatment of hypertension and heart failure) starting after their ablation procedure. The primary study endpoint will be any atrial tachyarrhythmia episode (AF, AFL or atrial tachycardia) lasting greater than one minute detected via the implanted cardiac monitor after CTI ablation during long-term follow-up. The incidence of new-onset AF after CTI ablation will be compared between subjects randomized to be treated with usual care vs. those treated with usual care plus spironolactone on an intention to treat basis.
The purpose of this study is to accurately determine, using an implantable rhythm monitor, the long-term incidence of new atrial fibrillation after ablation of atrial flutter in those treated with spironolactone compared with standard medical therapy.