Accuracy and Feasibility of Simplified Doppler-Based Left Ventricular Ejection Fraction

Abstract

Calculation of left ventricular (LV) ejection fraction (EF) by Doppler stroke volume and end-diastolic volume (EDV) derived from LV diastolic diameter (LVIDD) could be reliable and feasible in clinical practice. In subjects with a wide range of LV volumes and EFs, magnetic resonance imaging (MRI) was used to evaluate the accuracy of common formulas (Teichholz and Z method) to estimate EDV from LVIDD (EDVTeich; EDVZ) versus volumetric EDV. The accuracy of simplified Doppler-EF was tested in a separate study sample versus real-time 3-dimensional (RT3D) echocardiography and versus bidimensional Simpson's method. A new equation to calculate EDV from LVIDD was derived using MRI and tested in the RT3D echo samples. Feasibility of Doppler-EF was tested in a third sample of consecutive inpatients and outpatients. In the MRI sample, EDVTeich was greater whereas EDVZ was smaller than volumetric EDV (both p <0.01); however, a quadratic equation estimated EDV from LVIDD with accuracy (R² = 0.97). In the echocardiographic sample, independent of severe segmental wall motion abnormalities, EDVTeich was greater whereas EDV using Simpson's method was smaller than RT3D EDV (all p <0.05); Doppler-EF using EDVTeich was lower compared with EF by Simpson's rule or by RT3D-EF (all p <0.01). However, RT3D-EF showed no differences compared with Doppler-EF when EDV was calculated by the novel MRI-derived equation. Feasibility was 95% for Doppler-EF and 72% using Simpson's method. In conclusion, equations estimating EDV from LVIDD affect the accuracy of simplified Doppler-EF. However, Doppler-based EF may be accurate and feasible even in the presence of LV contractile asynergy.