January 14, 2015 – Emily Zeitler, MD, and her colleagues examined data from more than 2,300 patients enrolled in the HF-ACTION study.
Patients who receive implantable cardiac devices can improve their exercise capacity through exercise training, but the devices may also negate any benefits gained from the exercise.
The DCRI’s Emily Zeitler, MD (pictured); Jonathan Piccini, MD, MHS; Anne Hellkamp, MS; Kevin Jackson, MD; Stephen Ellis, PhD; William Kraus, MD; Christopher O’Connor, MD; and their colleagues recently sought to determine whether heart failure patients’ outcomes with exercise training were associated with ventricular pacing type. The results appear in this month’s issue of the Journal of Cardiac Failure.
More than 5 million Americans have heart failure, and approximately half of these people have an implanted cardiac pacemaker or cardioverter defibrillator. Little is known about the effect of physical exercise on these patients, particularly about the effect of exercise training in patients with right ventricular pacing versus biventricular pacing. The Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION) study found that heart failure patients who underwent exercise training experienced improved health-related quality of life and a slightly reduced chance of death and hospitalization. In this study, the researchers used patient data from HF-ACTION to determine whether the type of ventricular pacing influences exercise benefit in patients with cardiac devices.
HF-ACTION randomized 2,331 heart failure patients with a left ventricular ejection fraction equal to or less than 35 percent to standard care plus exercise training or standard care alone. Of these patients, 1,118 (48 percent) had an implanted cardiac rhythm device: 683 with right ventricular and 435 with biventricular pacemakers. Exercise training consisted of supervised walking, treadmill use, or cycle ergometer use. Exercise capacity was measured using cardiopulmonary exercise testing and maximal oxygen consumption.
The researchers found that exercise training did not lead to increased death or hospitalization for any of the study groups. All groups, regardless of exercise regimen or device status, showed an improvement in functional capacity, with the exception of standard care patients with biventricular pacemakers, who saw no change in maximal oxygen consumption. Patients who underwent exercise training saw the greatest gains in both cardiopulmonary exercise tests and maximal oxygen consumption. Of patients who were randomized to exercise training, gains in exercise capacity were similar between patients with and without devices.
However, the aggregate data suggest that the beneficial effect of exercise training observed in patients without cardiac devices may be attenuated in patients with devices. The researchers suggested ventricular pacing type may play a role in this phenomenon, but further study is needed to better understand the relationship between cardiac pacing and exercise training.