Are Physical Training Programs Safe for Patients with Cardiovascular Events?

Although physical exercise and exercise training was reported to have positive anti-arrhythmic effects in patients with paroxysmal artrial fibrillation, researchers emphasized there is limited data about the safety of and effects of exercise on patients heart failure with atrial fibrillation.

To determine whether exercise-training outcomes in patients with heart failure varied according to their atrial fibrillation status, Nancy Luo, MD (pictured) with the Division of Cardiology at Duke University Medical Center in Durham, NC, and fellow researchers from Duke Clinical Research Center and hospitals in New York, Virginia, Michigan, and Pennsylvania, conducted a study reassessing data from a 2008 study referred to as the HF-ACTION trial.

The study by Luo and colleagues fills a gap in research, providing data that characterized "the implications of exercise training in individuals with both heart failure and atrial fibrillation and their risk for future heart failure events," and determined that not only is exercise safe for heart failure patients with atrial fibrillation, it can also provide significant, albeit modest, improvements in function and quality of life for patients with atrial fibrillation.

The multi-center, randomized, controlled HF-ACTION trial, lead by Christopher M. O'Conner, MD, of Duke Clinical Research Institute, took place between 2003-2007. The study included 2,331 ambulatory patients with heart failure from 82 clinics in North America. Study participants were split into 2 groups: one received exercise training, and the other was encouraged to complete 30 minutes of exercise per day.

The training group completed 36 targeted exercise sessions (3 per week) during the first 3 months of the study, goals were increased in follow ups at 4-6 month and 10-12 months after the study start, and then at regular intervals during the next few years (average of 30 months). The study concluded that exercise training was safe for patients with heart failure, and that exercise training in addition to their care regimen saw a modest reduction in mortality and hospitalization related to heart failure.

In the study completed by Luo and colleagues, data from the HF-ACTION trial was reexamined "To (1) identify significant arrhythmias or ischemia that would prevent safe exercise training, (2) determine appropriate levels of exercise training, and (3) establish training heart rate ranges.

In order to determine interaction between exercise training and AF, the study used data from the HF-ACTION cohort, and applied Cox models to assess treatment effects and "post-randomization atrial fibrillation events diagnosed via hospitalizations for atrial fibrillation and reports of serious arrhythmia caused by atrial fibrillation."

The original HF-ACTION trial had no criteria for inclusion or exclusion of patients with heart failure and atrial fibrillation, and therefore provided significant data for comparison of exercise outcomes on patients with and without atrial fibrillation. Baseline atrial fibrillation diagnosis was based on presence of atrial fibrillation at during stress tests in the HF-ACTION study, and via reported medical history.

Follow up data from the original HF-ACTION study including data on atrial fibrillation hospitalizations and adverse arrhythmia, allowed researchers to "asses the association between exercise training and future atrial fibrillation events in the full trail population as well as by baseline atrial fibrillation status."

The study by Luo and colleagues focused on data for 1984 of the patients enrolled in the HF-ACTION study, and found that of patients with atrial fibrillation had significantly higher instances of comorbidities including myocardial infarction, diabetes, and renal function issues; lower usage of beta-blockers, higher usage of diuretics and anti-arrhythmic medications; and a lower baseline exercise capacity at the start of the exercise regimen. However, Luo reported, atrial fibrillation patients had similar improvements in exercise volume over the 3-month regimen.

The study showed there was no evidence to conclude that patients with atrial fibrillation had any increased risk of hospitalization or mortality in comparison with patients without atrial fibrillation. Luo and colleagues determined that no evidence of differential effects of "exercise training based on atrial fibrillation status."

Improvements in health status of patients with atrial fibrillation in the exercise program were consistent with the results in the overall population, and a "clinically noticeable improvement of 5 or more points" on the Kansas City Cardiomyopathy Questionnaire (KCCQ) in regards to health-related quality of life.

Patients with atrial fibrillation received similar modest, but significant health benefits, from the exercise regimen to non- atrial fibrillation population based on clinical outcomes. Patients also showed no increased risk of atrial fibrillation events in association with exercise regimens, confirming, according to Luo and colleagues, that exercise programs for this population carry no associated risks to patient safety.

The study's findings support recommendations for exercise in all patients with heart failure regardless of atrial fibrillation status, as a method of improving heart function and quality of life. Luo and colleagues suggest that future trials are necessary to develop criteria for safety and efficacy of specific exercise protocols, which may help "identify patients most likely to improve" with exercise regimens.

The article "Exercise Training in Patients With Chronic Heart Failure and Atrial Fibrillation" appears in the April 2017 issue of The Journal of the American College of Cardiology.