Li M, Lu Y, Fang C, Zhang X

Echocardiography. 2017 Nov;34(11):1640-1648. doi: 10.1111/echo.13675. Epub 2017
Sep 19.

PURPOSE: Heart failure (HF) is a multifactorial entity that combines derangements
in both systolic and diastolic function. The relationship between systolic and
diastolic function and exercise capacity is not fully understood. We sought to
determine the mechanisms linking cardiac function and exercise tolerance in
patients with HF.
METHODS: One hundred fifty-six subjects with different cardiac function levels
were included in the study. Subjects’ 2D echocardiographic, 3D speckle tracking
echocardiographic, and cardiopulmonary exercise testing (CPET) data were
collected.
RESULT: The amount of untwisting at 25% of the untwist duration (25%Untwist) and
global longitudinal peak systolic strain (GLS) showed the best positive
correlations with peak oxygen uptake (peakVO2 ) (r = .41; P < .001 and r = .32;
P < .001, respectively), while the left ventricular ejection fraction (EF) was
weakly correlated with peakVO2 . The 25%Untwist value was negatively correlated
with the carbon dioxide equivalent slope (VE/VCO2 ) (r = -.49; P < .001). Both
E/e and the left atrium volume index (LA index) exhibited good positive
correlations with VE/VCO2 (r = .39; P < .01 and r = .32; P < .001). In the
multiple regression analysis, the best predictive model for the peakVO2 included
the 25%Untwist, GLS, and E/e, explained 64% of the variation in peakVO2 , with
25%Untwist explaining 17.6% of the variation. Including EF in the model explained
only 3.1% of the variation in peakVO2 . In a multivariable model for VE/VCO2 ,
25%Untwist was the strongest independent predictor, explaining 23% of the
variance in VE/VCO2 .
CONCLUSION: Left ventricular early diastolic function is a modest independent
predictor of aerobic exercise capacity. The 25%Untwist value is a good indicator
of cardiac diastolic function.