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Updated: Feb 27, 2026
Author Spotlight: Integrating Alveolar-Capillary Reserve Measurements in Exercise Adaptation and Therapeutic Strategies
Published on: February 2, 2024
Contractile reserve and cardiopulmonary exercise parameters in patients with dilated cardiomyopathy, the two
Kegan J Moneghetti1,2, Yukari Kobayashi1,2, Jeffrey W Christle1
1Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.
Insights
Cardiopulmonary exercise testing (CPX) and echocardiography reveal complementary insights into dilated cardiomyopathy (DCM). Percent change in left ventricular (LV) contractile reserve offers a more reliable measure of ventricular response during exercise.
Area of Science:
- Cardiology
- Exercise Physiology
- Diagnostic Imaging
Background:
- Left ventricular (LV) contractile reserve assessed by imaging and cardiopulmonary exercise testing (CPX) predicts outcomes in dilated cardiomyopathy (DCM).
- Limited studies have explored the relationship between these two assessment methods in DCM patients.
Purpose of the Study:
- To investigate the relationship between echocardiographic measures of LV contractile reserve and CPX parameters in patients with DCM.
- To determine which metric of ventricular response (absolute or percent change) is less dependent on baseline LV function.
Main Methods:
- A cohort of 75 ambulatory DCM patients underwent stress treadmill echocardiography concurrently with CPX.
- LV contractile reserve was quantified by absolute and percent change in ejection fraction (LVEF) and strain (LS).
- Exercise capacity (peak oxygen uptake, peak VO2) and ventilatory efficiency (VE/VCO2 slope) were measured.
Main Results:
- Peak cardiac output strongly correlated with peak VO2 (r=.63, P<.001), explaining over 70% of its variance when combined with demographic factors.
- Left ventricular ejection fraction (LVEF) and longitudinal strain (LS) showed weak associations with peak VO2.
- Percent change in LVEF demonstrated greater independence from baseline LV function compared to absolute change.
Conclusions:
- Echocardiographic contractile reserve and CPX provide complementary prognostic information in DCM.
- Percent change in LV contractile reserve is recommended for analyzing ventricular response due to its reduced dependence on baseline function.
Background:
Left ventricular (LV) contractile reserve assessed using imaging and cardiopulmonary exercise testing (CPX) has been shown to predict outcome in patients with dilated cardiomyopathy (DCM). Few clinical studies have, however, analyzed the relationship between them.
Methods:
A cohort of 75 ambulatory patients with DCM underwent stress treadmill echocardiography with CPX. LV contractile reserve was calculated as absolute change (ΔLVEF=LVEFpeak -LVEFrest ) and percent change (%LVEF=[(LVEFpeak -LVEFrest )/LVEFpeak) ]×100) in LVEF, circumferential and longitudinal strain (LS). Exercise capacity was measured as peak oxygen uptake (peak VO2 ) and ventilatory efficiency as the slope of minute ventilation to CO2 production (VE/VCO2 slope). Values of contractile reserve were compared to matched controls. We also explored which metric of ventricular response (absolute or percent change) was less dependent on baseline LV function.
Results:
Patients with DCM had a mean age, rest and peak LVEF of 44±10 years, 42±10% and 50±12%, respectively. Among parameters of contractile reserve, peak cardiac output was the strongest parameter associated with peak VO2 (r=.63, P<.001). Along with age, sex, and BMI, it explained more than 70% of the variance in peak VO2 . In contrast, LVEF and LS were only weakly related to peak VO2 . With regard to ventilatory efficiency, the strongest parameter that emerged was right atrial volume index (r=.36, P<.001). Percent change in LVEF was more independent of baseline function than absolute change.
Conclusion:
Echocardiographic contractile reserve and CPX provide complementary information. Percent change in contractile reserve was most independent of baseline function, therefore may be preferred when analyzing the ventricular response to exercise.
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