04.10.2016
Ability of atrial fibrillation patients to get up and move pays dividends

by Ed Susman
Contributing Writer, MedPage Today

CHICAGO — A pair of studies indicate that patients diagnosed with atrial fibrillation who can exercise have better outcomes than those who are sedentary, researchers said here at the annual scientific sessions of the American College of Cardiology.

In one study, Marco Proietti, MD, a PhD candidate at the University of Birmingham in the United Kingdom, reported that when compared with people with atrial fibrillation who perform little of no exercise, less than 90% survive a year while the survival among those with modest to intense exercise is more than 95%.

And in another study, Mohamed Elshazly, MD, a senior cardiology fellow at the Cleveland Clinic, suggested that heart failure patients with atrial fibrillation treated with rate control strategies have reduced exercise capacity – even with preserved left ventricular function – which increases their risk of mortality, and those patients might be better served being treated with rhythm control.

The take home message from the studies, said Gaurav Upadhyay, MD, assistant professor of medicine at the University of Chicago, “is that physical exercise is good for you, and atrial fibrillation is bad.”

In his study, Proietti and colleagues analyzed the so-called ‘real world’ population enrolled in the EURObservational Research Programme Pilot Survey on Atrial Fibrillation (EORP-AF) General Registry. From the original cohort, data about physical activity were available for 2,439 evaluable patients during the period from February 2012 to March 2013.

They were stratified by the amount of exercise performed weekly over a 2-year period. He found that 947 of the patients of 38.8% of the cohort were classified as performing no exercise (less than 3 hours of exercise a week for less than 2 years); 847 patients or 34.7% performed occasional exercise (less than 3 hours a week for 2 years or more); 550 patients or 22.6% were classified as regular exercisers (3 hours or more exercise a week for 2 years or more) and 115 patients or 4.7% performed intense physical activity (more than 7 hours a week for 2 years or more).

The group that performed little or no exercise, cardiovascular death occurred in about 5.9% of patients over the course of the study compared with rates of less than 2% for the other groups (P<0.001); and all cause mortality was about 12% in the group that exercised little compared to 2% to 4% in the other groups (P<0.001).

There was no significant differences between the groups due to stroke or embolism, Proietti reported in his poster discussion presentation. He also noted physical activity wasn’t associated with arrhythmia progression from paroxysmal AF to more established patterns.

“Efforts to increase physical activity amongst atrial fibrillation patients may improve outcomes in these patients,” he said.

In the Cleveland Clinic study, Elshazly and colleagues employed propensity matching techniques to compared outcomes among patients with heart failure and atrial fibrillation – but who also had preserved left ventricular function – with heart failure patients without atrial fibrillation. The patients in the study had a left ventricular ejection fraction of about 58%. About 68% of the these patients were on beta blockers and another 20% were on digitalis.

The 242 patients identified in the study with heart failure and atrial fibrillation and preserved left ventricular function were compared with 484 patients who did not have an atrial fibrillation diagnosis.

Previous studies had shown that exercise in patients with reduced left ventricular function and showed that restoration of sinus rhythm had a positive impact on exercise hemodynamics, improved symptoms and quality of life. But those with preserved left ventricular function had not been studied, the researchers noted.

“Atrial fibrillation patients with good heart rate control – a mean resting heart rate of 70 bpm and a peak exercise heart rate of 130 bpm demonstrated evidence of impaired peak exercise tolerance,” Elshazly said. “Atrial fibrillation was associated with increased total mortality at 8 years with early curve separation.”

“Our study, the largest of its kind, this provides mechanistic evidence that rhythm control strategy may potentially improve peak exercise capacity and survival, a finding that requires future prospective appraisal in this patient population,” he said.

• Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco
• This activity is part of our Clinical Context curriculum in Strokes