A method for calculating left ventricular ejection fraction non-invasively from left ventricular arterial coupling (Ees/Ea)

Abstract

Abstract Background: Ejection fraction (EF) is a standard method of evaluating of cardiac function. EF is useful to monitor cardiac function and circular management during general anesthesia, but it is impossible to calculating EF using ultrasonography continuously and non-invasively. The aim of our study is development of the method to estimate EF non-invasively from left ventricular arterial coupling (Ees/Ea). Methods: Ees/Ea can be estimated non-invasively from pre-ejection period (PEP), ejection time (ET), end-systolic pressure (Pes) and diastolic pressure (Pad). These parameters were calculated from a vascular screening system, VeSera 1000/1500(Fukuda Denshi Co., Ltd., Tokyo, Japan). The left ventricular efficiency (Eff) as a pump, is defined as the ratio of external work (EW) to myocardial oxygen consumption, as strongly correlated to pressure-volume area (PVA). Eff can be calculated from Ees/Ea, and EF(EFeff) was approximated from Eff. We measured EF using transthoracic echocardiography, and compared it with EFeff. Results: The study included 44 healthy adults (36 males, 8 femals). EFecho was 66±5 %, EFeff was 57±9 %. There was a positive correlation between EF and EFeff (R2 = 0.219, p < 0.05 ). Result of Bland-Altman analysis, the limits of agreement were – 7.5 to 24.4 %, the PE was 24%. Conclusion: The results suggest that EF can be measured non-invasively using left ventricular arterial coupling.