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 included in the Guidant-sponsored Advancent SM, a national registry of patients with impaired left ventricular function. The mean ejection fraction of the participants was 31%. Nearly three-quarters of them 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 treated with 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 the participants in Advancent SM were being treated with a β-blocker, whereas 82% were on an ACE inhibitor or angiotensin receptor blocker. These drugs also appeared to protect against AF. However, lipid-lowering therapy exhibited a protective effect independent of and additive to that of these other drugs.
The mechanism of lipid-lowering therapy's protective effect against AF is unclear so far.
Some recent studies have implicated oxidative stress in the etiology of the arrhythmia. Statins are known to have antioxidant properties, Dr. Hanna noted.
Elsewhere 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 conducted to date has predominantly involved retrospective evaluations of registry data or the landmark clinical trials that established the current indications for these drugs, said Dr. Kowey, who is a professor of medicine at Jefferson Medical College in 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,” Dr. Kowey said.
“But I can also tell you that what we've seen so far as a treatment effect has certainly not been very robust,” he said.
“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,” Dr. Kowey added.