Exercise cardiac magnetic resonance imaging in heart failure with preserved ejection fraction: impact of central obesity on exercise capacity - the EXPOSURE study
M Lobeek, T P Willems, S M Ng, M Rienstra, B D Westenbrink, D J Van Veldhuisen, T M GorterAbstract
Background
Central obesity is a key contributor to heart failure with preserved ejection fraction (HFpEF). The mechanisms by which central obesity influences exercise capacity remain unclear. The present study examined associations between parameters of central obesity with exercise capacity and cardiac response to exercise in patients with HFpEF.
Methods
In the prospective, observational study, consecutive patients with HFpEF underwent cardiopulmonary exercise testing (CPET) and exercise cardiac magnetic response (CMR) imaging using a supine bicycle ergometer. CMR was acquired at rest, at 40% of maximum exercise and at maximum exercise (defined as 60% of peak CPET wattage). Cardiac parameters, including left and right ventricular (LV/RV) volumes, ejection fraction, stroke volume and cardiac output were quantified using CVI42. Linear regression analyses were used to associate waist circumference (WC) and waist-to-height ratio (WHtR) with exercise capacity and cardiac function at rest and during exercise.
Results
In total, 40 patients were enrolled, of whom 36 patients had adequate image quality for further analysis. Mean age was 71±8 years, with 56% females, 35% had a BMI ≥30 kg/m2, 100% had an increased WC and 83% had an increased WHtR. Higher WHtR was associated with lower peak VO2 (β=-0.007, p=0.014). Additionally, higher WHtR was associated with a higher increase in RV stroke volume from rest to maximum exercise (β=0.001, p=0.048) and higher WC was associated with a higher increase of RV end-diastolic volume and RV stroke volume from rest to maximum exercise (β=0.300, p=0.017, β=0.599, p=0.012, respectively), while BMI was not associated with the difference in RV volume from rest to maximum exercise.
Conclusions
Anthropometric measures of central obesity were associated with RV adaptations to increased volume load during exercise and with reduced exercise capacity, suggesting that central obesity may contribute hemodynamically to exercise intolerance in patients with HFpEF.