Exercise Training as Therapy for Heart Failure Current Status and Future Directions

TLDR: This landmark study leaves several unanswered key questions, including the role of exercise dose; the relative benefit of different types of aerobic exercise, including high-intensity interval training (HIIT), and resistance, training relative to aerobic training; combination of exercise training with other therapies; optimization of adherence; benefit for older patients with HF, those with HFpEF or multiple comorbidities, and those with acute decompensated HF.

Abstract: Despite a variety of pharmacological and device therapies for persons with chronic heart failure (HF), prognosis and quality of life (QOL) remain poor. The need for new effective strategies to improve outcomes for patients with HF is underscored by persistently high mortality, morbidity, healthcare use, and costs associated with HF, with >1 million US HF hospitalizations at an estimated direct and indirect cost in the US of $40 billion in 2012.1 Exercise intolerance is a primary symptom in patients with chronic HF, both those with preserved ejection fraction (HFpEF) and reduced ejection fraction (HFrEF), and is a strong determinant of prognosis and of reduced QOL.2 Exercise training improves exercise intolerance and QOL in patients with chronic stable HFrEF, and has become an accepted adjunct therapy for these patients (Class B level of evidence) based on a fairly extensive evidence base of randomized trials, mostly small.3 The National Heart, Lung, and Blood Institute–funded Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION) trial compared an individualized, supervised, and home-based aerobic exercise program plus guideline-based pharmacological and device therapy with guideline-based therapy alone in persons with HFrEF. The exercise arm showed a modest reduction in cardiovascular hospitalizations and mortality and improved QOL.4,5 However, problems with adherence in the exercise arm probably dampened the potential benefit. This landmark study leaves several unanswered key questions, including the role of exercise dose; the relative benefit of different types of aerobic exercise, including high-intensity interval training (HIIT), and resistance, training relative to aerobic training; combination of exercise training with other therapies; optimization of adherence; benefit for older patients with HF, those with HFpEF or multiple comorbidities, and those with acute decompensated HF. The National Heart, Lung, and Blood Institute convened a working group of experts on June 11, …