Non-invasive measuring of the acceleration of contraction of the left ventricle with the Doppler echocardiography
Background: Echocardiographically measured ejection fraction (EF) of the left ventricle (LV) is the most useful standard of the LV systolic function. Its limitations are poor delineation of the LV endocardium, pronounced regional disorders of contractility, dyssynchrony of the LV and in particular significant mitral regurgitation. The aim of this research is to evaluate the advantage of Doppler indices of left ventricular function such as index of acceleration of contraction of the LV (AccLV) over EF in patients with heart failure.
Methods: We performed a prospective observational study. We included 45 patients with known chronic heart failure and 76 healthy subjects. We performed standard echocardiographic measurements. AccLV was calculated by the following formula: AccLV = Vmax LVOT/dt × EDV [cm/s2 ml]. Vmax LVOT represents the maximum velocity during ejection in the left ventricular outflow tract (LVOT), dt stands for the interval from the beginning of the LV contraction to the achieved Vmax LVOT, EDV represents end-diastolic volume of the LV.
Results: Between patients and healthy subjects we observed statistically significant differences in mean EF values (65.4 ± 6.7 % vs. 38.6 ± 18.0 %; p < 0.001) and of AccLV (12.1 ± 2.88 cm/s2ml vs. 4.4 ± 2.1 cm/s2ml; p < 0.001). Receiver operating characteristic (ROC) curve showed higher area under the curve values for AccLV in comparison to EF (0.996 vs. 0.897). In the patient group we observed more important correlation between AccLV index and the New York Heart Association (NYHA) functional classes (r = − 0.657; p < 0.001), than between EF and the NYHA classes (r = − 0.539; p < 0.001).
Conclusions: We could distinguish with higher accuracy between healthy subjects and patients with heart failure LV by calculated AccLV in comparison to EF. AccLV values correlated with NYHA functional classes in patients with heart failure better than EF values.