Impaired Exercise Tolerance in Heart Failure With Preserved Ejection Fraction: Quantification of Multiorgan System Reserve Capacity.

Exercise intolerance is a principal feature of heart failure with preserved ejection fraction (HFpEF), whether or not there is evidence of congestion at rest. The degree of functional limitation observed in HFpEF is comparable to patients with advanced heart failure and reduced ejection fraction. Exercise intolerance in HFpEF is characterized by impairments in the physiological reserve capacity of multiple organ systems, but the relative cardiac and extracardiac deficits vary among individuals. Detailed measurements made during exercise are necessary to identify and rank-order the multiorgan system limitations in reserve capacity that culminate in exertional intolerance in a given person. We use a case-based approach to comprehensively review mechanisms of exercise intolerance and optimal approaches to evaluate exercise capacity in HFpEF. We also summarize recent and ongoing trials of novel devices, drugs, and behavioral interventions that aim to improve specific exercise measures such as peak oxygen uptake, 6-min walk distance, heart rate, and hemodynamic profiles in HFpEF. Evaluation during the clinically relevant physiological perturbation of exercise holds promise to improve the precision with which HFpEF is defined and therapeutically targeted.