NEW ORLEANS — Lipid-lowering therapy appears to protect against the development of atrial fibrillation in patients with impaired left ventricular function, Ibrahim R. Hanna, M.D., reported at the annual meeting of the Heart Rhythm Society.
He presented data on 25,268 patients in the Guidant-sponsored Advancent SM, a national registry of patients with impaired left ventricular function. Their mean ejection fraction was 31%. Nearly three-quarters had ischemic cardiomyopathy.
Patients on lipid-lowering therapy—the vast majority of it consisting of statins—had a 34% reduction in the relative risk of having paroxysmal or persistent atrial fibrillation in a multivariate analysis controlling for potential confounders, according to Dr. Hanna of Emory University, Atlanta.
The prevalence of atrial fibrillation (AF) among patients on lipid-lowering therapy was 25%. This was a 23% lower rate than in patients not on lipid-lowering therapy, regardless of whether they were hyperlipidemic.
Overall, 79% of Advancent SM participants were on a β-blocker; 82% were on an ACE inhibitor or angiotensin receptor blocker. These drugs also appeared to protect against AF. However, lipid-lowering therapy had a protective effect independent of and additive to that of the other drugs.
The mechanism of lipid-lowering therapy's protective effect against AF is unclear. Some recent studies have implicated oxidative stress in the etiology of the arrhythmia. Statins are known to have antioxidant properties, Dr. Hanna noted.
Also at the meeting, Peter R. Kowey, M.D., said one of the hottest areas in drug development for suppression of AF involves therapies already being used in other contexts for patients who have heart disease.
The drug classes being looked at most extensively are the statins, because of their anti-inflammatory and other pleiotropic properties, and the ACE inhibitors/angiotensin receptor blockers. The research to date has predominantly involved retrospective looks at registry data or the landmark clinical trials that established the current indications for these drugs, said Dr. Kowey, professor of medicine at Jefferson Medical College, Philadelphia.
“At every national meeting this year there have been at least three or four abstracts in which people have delved back into assorted databases to try to understand in a retrospective fashion if there was a signal of these drugs preventing atrial fibrillation. I think it's fair to say that what we've seen so far indicates that in fact there is a signal,” he said. “What we've seen so far as a treatment effect has certainly not been very robust. Unless we see some major increase in the amount of suppression of arrhythmias in these trials, it's unlikely that these drugs will be used as primary therapies, although they might be very useful accessory therapies in patients who are at risk.”