• Cardiology Clinical Trials
• Arrhythmias

Olmesartan does not reduce the incidence of atrial fibrillation (AF) episodes among patients with paroxysmal AF without structural heart disease. Andreas Goette, MD, Department of Cardiology, St. Vincenz-Hospital, Paderborn, Germany, discussed findings from the Angiotensin II Antagonist in Paroxysmal Atrial Fibrillation (ANTIPAF; NCT0098137) trial. ANTIPAF was conducted by the German Competence Network on Atrial Fibrillation (AFNET), an interdisciplinary national research network that is funded by the German Federal Ministry of Education and Research.

AF, the most common cardiac arrhythmia, is a progressive illness that is characterized by increased episodes over time. While angiotensin II antagonists (ARBs) may potentially reduce the incidence of AF without the side effects that are often seen with other antiarrhythmic therapies, this suggestion is based on numerous meta-analyses and has not yet been supported by focused prospective trial data. ANTIPAF was designed to evaluate the impact of the ARB olmesartan on episodes of paroxysmal AF in a prospective, randomized, double-blind, placebo-controlled trial.

ANTIPAF included 425 patients with documented paroxysmal AF (≤6 months), stratified by β-adrenoceptor antagonist use, who were randomized to receive either olmesartan 40 mg daily (n=214) or placebo (n=211) over the course of 12 months. The groups were well matched at baseline. Those who took ARBs and ACE inhibitors, or Class I and III antiarrhythmic drugs prior to randomization and those who initiated β-blocker therapy after randomization were excluded from participation in this study. The primary endpoint was percentage of days with documented episodes of paroxysmal AF during 12 months of follow-up (defined as the number of days with PAF/number of days with at least one readable Tele-ECG recording). A total of 207 Tele-ECGs per patient were performed, amounting to 1.12 Tele-ECGs per patient and follow-up day. Secondary endpoints included time to first recurrence of documented AF, time to persistent AF, time to prescription of “recovery medication” (amiodarone), quality of life measures, percentage of days with documented paroxysmal episodes or suspected persistent AF after 90 days of therapy, number of hospitalizations for cardiovascular (CV) reasons, number of unscheduled outpatient visits for CV reasons, and number of cerebrovascular events.

There was no significant difference between olmesartan and placebo for AF burden, as determined by the primary endpoint. The cumulative incidence of AF recurrence and persistent AF was also similar between the two groups. The cumulative event rates at 12 months, as measured by the secondary outcomes, were comparable for both groups. However, time to prescription of “recovery medication” favored olmesartan (HR, 0.41; 95% CI, 0.186 to 0.904; p=0.0224). The rate of serious adverse events was similar for both groups.

Olmesartan did not reduce the number of AF episodes in this cohort compared with placebo. Therefore, ARB therapy may not be appropriate as first-line treatment for paroxysmal AF in the absence of other indications. The only intergroup difference that was noted within ANTIPAF was the time to prescription of amiodarone for recovery treatment. All other measures were comparable between olmesartan and placebo, suggesting that previous meta-analysis findings may have been due to variables that were independent of ARB treatment.

• © 2010 MD Conference Express