Ablation during mitral valve surgery reduces atrial fibrillation

March 16, 2015

SAN DIEGO (March 16, 2015) -- Patients with atrial fibrillation who received ablation while they were already undergoing surgery to correct a leaky heart valve had fewer episodes of atrial fibrillation a year later compared to patients who had the valve surgery alone, according to a study presented at the American College of Cardiology's 64th Annual Scientific Session.

The patients who received ablation along with mitral valve surgery had no more deaths, adverse cardiac events or hospitalizations than patients who only received the valve surgery alone, but they were more likely to require a pacemaker.

The study, which included 260 patients within the Cardiothoracic Surgical Trials Network, a clinical research network involving 20 U.S. and Canadian hospitals, is the first appropriately powered randomized clinical trial to assess the use of ablation in patients already undergoing mitral valve surgery. Half of the patients were randomly assigned to receive mitral valve surgery alone, while the other half also received surgical ablation. All of the study participants had persistent or long-standing persistent atrial fibrillation and were undergoing surgery to repair or replace the heart's mitral valve, which controls movement of blood from the left atrium to the left ventricle.

Of the patients who received ablation and mitral valve surgery, 63 percent were free from atrial fibrillation at six and 12 months after surgery, while 29 percent of patients who received mitral valve surgery alone were free from atrial fibrillation at those time points. Mitral valve surgery is typically performed to correct a leaking or narrowed valve. Although the procedure is unrelated to atrial fibrillation, many patients in need of valve repair also have atrial fibrillation, so surgeons have begun combining the two procedures in order to address both cardiac issues at the same time.

"Although surgeons are widely performing ablation at the time of mitral valve surgery, there is a great deal of variation with regard to when it is done, how it is done and which patients receive it," said Marc Gillinov, M.D., the Judith Dion Pyle Chair in Heart Valve Research at Cleveland Clinic and the study's lead author. "We sought to conduct a well-designed randomized controlled trial to answer fundamental questions about whether this procedure is successful and how it is best done."

In the absence of strong clinical guidance regarding the use of ablation with mitral valve surgery, the decision is left largely up to physician preference, Gillinov said. About two-thirds of surgeons currently perform ablation during mitral valve surgery for patients with persistent atrial fibrillation, while one-third do not.

The National Institutes of Health and Canadian Institutes for Health Research supported the design and conduct of the trial.

While the patients receiving ablation were significantly more likely to be free of atrial fibrillation six and 12 months after surgery, the study showed no significant differences in rates of death, adverse cardiac events or hospitalization. Patients receiving the mitral valve surgery alone reported a slightly lower quality of life because more of these patients said they still experienced daily atrial fibrillation a year after the surgery.

"I think what this shows is that, in the mitral valve surgery patient who has persistent atrial fibrillation, you will achieve better rhythm control by performing ablation, without any increase in mortality or other adverse cardiac events," Gillinov said.

However, the analysis also revealed one potential downside to including ablation with mitral valve surgery. Patients receiving the ablation along with the mitral valve surgery were 2.5 times more likely to require the implantation of a pacemaker in the year following their surgery. The reason for this difference is unknown and warrants further study, Gillinov said.

Because there are several tools and techniques physicians can choose when performing surgical ablation, researchers decided to randomly assign patients receiving the ablation to either pulmonary vein isolation, in which the surgeon uses heat or cryothermy energy to destroy a small area of tissue in the heart, or a biatrial Maze lesion, in which the surgeon makes a complex series of lesions to correct abnormal electrical impulses. The analysis showed no significant differences in the outcomes for patients undergoing the two procedure types, though a larger study would help to elucidate any differences, Gillinov said.

Because patients have only been tracked for one year, the results do not yet provide a clear picture of the full spectrum of potential differences in cardiovascular outcomes. The researchers will continue to track patients to assess any long-term differences in survival, hospitalization, stroke and other outcomes.
-end-
This study was simultaneously published online in the New England Journal of Medicine at the time of presentation.

The ACC's Annual Scientific Session brings together cardiologists and cardiovascular specialists from around the world each year to share the newest discoveries in treatment and prevention. Follow @ACCMediaCenter and #ACC15 for the latest news from the meeting.

The American College of Cardiology is a 49,000-member medical society that is the professional home for the entire cardiovascular care team. The mission of the College is to transform cardiovascular care and to improve heart health. The ACC leads in the formation of health policy, standards and guidelines. The College operates national registries to measure and improve care, provides professional medical education, disseminates cardiovascular research and bestows credentials upon cardiovascular specialists who meet stringent qualifications. For more information, visit acc.org.

American College of Cardiology

Related Atrial Fibrillation Articles from Brightsurf:

Atrial fibrillation less deadly than it used to be, but still cause for concern: BU study
A first-of-its-kind study by researchers from the Boston University School of Public Health (BUSPH) shows a decline in deaths related to atrial fibrillation (irregular heartbeat) over the last 45 years.

Postoperative atrial fibrillation does not impact on overall survival after esophagectomy
Volume 11, Issue 25 of Oncotarget reported that Administration of landiolol hydrochloride was found to be associated with reduced incidence of atrial fibrillation after esophagectomy for esophageal cancer in our previous randomized controlled trial.

People with atrial fibrillation live longer with exercise
More than 100,000 Norwegians have atrial fibrillation. They should be actively exercising for their health.

Atrial fibrillation among overweight people is not due to fat
In a recently published study, researchers from Aarhus University document that the risk of atrial fibrillation is not linked to the amount of body fat, but instead to large muscle mass, or more precisely, a high fat-free weight

Eating more protein could help ward off atrial fibrillation in women
Women who ate slightly more than the recommended daily amount of protein were significantly less likely to develop atrial fibrillation (AFib), a dangerous heart rhythm disorder that can lead to stroke and heart failure, when compared with those who consumed less protein, according to research being presented at the American College of Cardiology's Annual Scientific Session Together with World Congress of Cardiology (ACC.20/WCC).

Zebrafish teach researchers more about atrial fibrillation
Genetic research in zebrafish at the University of Copenhagen has surprised the researchers behind the study.

Personalized medicine for atrial fibrillation
The study, published in Europace, uses signals from implantable devices -- pacemakers and defibrillators -- to analyze electrical signals in the heart during episodes of atrial fibrillation.

Prescribing anticoagulants in the ED for atrial fibrillation increases long-term use by 30%
Patients prescribed anticoagulants after a diagnosis of atrial fibrillation in the emergency department are more likely to continue long-term use of medications to treat the condition, according to research published in CMAJ (Canadian Medical Association Journal).

Anticoagulant benefits for atrial fibrillation decrease with age
The net clinical benefit of anticoagulants for atrial fibrillation (AF) -- one of the most important causes of irregular heartbeats and a leading cause of stroke -- decreases with age, as the risk of death from other factors diminishes their benefit in older patients, according to a study led by researchers at UC San Francisco.

Research improves understanding of mechanism of atrial fibrillation
Mouse model studies show that noncoding DNA regions linked to atrial fibrillation risk can display long-range regulatory functions directed at Pitx2 gene and in this way predispose to the condition.

Read More: Atrial Fibrillation News and Atrial Fibrillation Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.