Correlation between myocardial deformation on three-dimensional speckle tracking echocardiography and cardiopulmonary...

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.

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.

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 .

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.