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Left ventricular diastolic dysfunction and exercise intolerance in obese heart failure with preserved ejection
T Jake Samuel1, Dalane W Kitzman2,3, Mark J Haykowsky4
1Department of Kinesiology, University of Texas at Arlington, Arlington, Texas.
American Journal of Physiology. Heart and Circulatory Physiology
|February 12, 2021
Summary
Left ventricular (LV) relaxation is impaired in older obese patients with heart failure with preserved ejection fraction (HFpEF). However, elevated LV filling pressures, not LV relaxation, are more strongly linked to reduced exercise capacity in these patients.
Area of Science:
- Cardiology
- Cardiovascular Imaging
- Exercise Physiology
Background:
- Heart failure with preserved ejection fraction (HFpEF) is a growing clinical challenge, particularly in older, obese populations.
- Reduced exercise capacity is a hallmark symptom of HFpEF, significantly impacting patient quality of life.
- The precise mechanisms linking cardiac dysfunction and exercise intolerance in this specific demographic remain incompletely understood.
Purpose of the Study:
- To test if early left ventricular (LV) relaxation is impaired in older obese patients with HFpEF.
- To investigate the relationship between impaired LV relaxation and decreased peak exercise oxygen uptake (peak V̇o2).
- To determine the relative contributions of LV relaxation and LV filling pressures to exercise intolerance.
Main Methods:
- Magnetic resonance imaging (MRI) with feature tracking was used to measure LV strain and strain rate in 79 older obese HFpEF patients and 54 controls.
- LV diastolic strain rates were indexed to cardiac preload using echocardiography-derived diastolic filling pressures (E/e').
- Correlations between indexed LV diastolic strain rates and peak V̇o2 were analyzed.
Main Results:
- Early LV circumferential diastolic strain rate was significantly impaired in HFpEF patients compared to controls.
- After indexing to E/e', differences in LV diastolic strain rates (circumferential, radial, longitudinal) between groups became more pronounced.
- Indexed LV diastolic strain rates showed only a modest correlation with peak V̇o2, largely driven by E/e' itself, indicating a stronger role for filling pressures.
Conclusions:
- Left ventricular (LV) relaxation is indeed impaired in older obese patients with HFpEF.
- While LV relaxation is compromised, it only modestly correlates with reduced peak exercise V̇o2.
- Elevated LV filling pressures demonstrate a stronger association with exercise intolerance, suggesting they are a more critical therapeutic target.
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