Left ventricular systolic function assessment in secondary mitral regurgitation: left ventricular ejection fraction vs. speckle tracking global longitudinal strain

Left ventricular (LV) ejection fraction (LVEF) is currently considered for the decision making of patients with mitral regurgitation (MR). However, LVEF represents change in LV volume between end-diastole and end-systole but does not characterize the intrinsic function of the myocardium. In contrast, speckle-tracking global longitudinal strain (GLS) characterizes myocardial deformation. The present study evaluated whether LV GLS may detect further impairment in LV systolic function in dilated cardiomyopathy patients with and without severe secondary MR matched based on LVEF. Patients with non-ischaemic dilated cardiomyopathy (N = 150, 59 ± 12 years old, 58% male) were included: 75 patients with severe secondary MR and 75 patients with none or less than mild MR matched 1 : 1 according to LVEF. The LV systolic function was evaluated by LVEF (following Simpson's biplane method), forward ejection fraction (forward stroke volume relative to LV end-diastolic volume), and speckle-tracking GLS. By definition, LVEF was comparable between the two groups (patients with severe MR 31 ± 10 vs. patients with no/mild MR 31 ± 10%, P = 0.93). However, patients with severe MR had significantly lower forward ejection fraction (29 ± 14 vs. 40 ± 18%, P < 0.001) and more impaired GLS (-8.08 ± 3.33 vs. -9.78 ± 3.78%, P = 0.004) compared with their counterparts. The presence of severe secondary MR was significantly associated with worse LV GLS (β 1.32, 95% confidence interval 0.14-2.49, P = 0.03). In patients with severe secondary MR, speckle-tracking GLS shows more deteriorated LV systolic function than LVEF.