Angiotensin II antagonist in paroxysmal atrial fibrillation (ANTIPAF) trial: rationale and study design

Atrial fibrillation (AF) is the most common cardiac arrhythmia. Recent experimental data and retrospective analyses of clinical trials suggest that increased levels of angiotensin II can induce an arrhythmogenic atrial substrate, which favours the occurrence of AF. The purpose of the ANTIPAF (Angiotensin II Antagonist in Paroxysmal Atrial Fibrillation) trial is to prove the principal concept that blockade of angiotensin II type 1 receptors with olmesartan medoxomil 40 mg/day suppresses paroxysmal AF episodes during a 12-month follow-up. The ANTIPAF trial is the first placebo-controlled trial analysing the occurrence of AF as the primary study endpoint.

Examination of the study hypothesis in a prospective, randomised, placebo-controlled, double-blind group comparison in patients with documented paroxysmal AF (total of 422 patients) stratified by beta-adrenoceptor antagonist use. The primary endpoint of the study is the percentage of days with documented episodes of paroxysmal AF identified on daily transtelephonic tele-ECG recordings. Patients will record and transmit at least one 1-minute ECG per day independent of symptoms. Furthermore, tele-ECG recordings will be transmitted in any case of symptomatic AF. The present paper summarises the rationale and design of the ANTIPAF trial.