Application of multiparametric cardiac measurement system in ejection fraction calculation

Abstract

Ejection fraction (EF) is the most used parameter for characterisation of Heart Failure (HF) condition. EF is commonly calculated using echocardiography, which is an expensive non–invasive method and not used in primary healthcare. Systolic time intervals (STI) represent a non-invasive and inexpensive method for determination of EF[1, 2]. Heart failure (HF) is the single most expensive diagnosis in medicine. 2–3% of adult population in developed countries have HF diagnosis. It is not detectable by ECG test and it is commonly detected in a late stage, when the process is irreversible [2-5]. In this paper, a multiparametric cardiac measurement system for determination of STI is presented. Measurement system consists of sensors for simultaneous acquisition of electrocardiographic (ECG), phonocardiographic (PCG), photopletysmographic (PPG) and cardiovascular (CV) pulsation signals. CV pulsation signals are measured by long period grating (LPG) fiber-optic sensors[6]. Two non-invasive methods for measuring systolic time intervals (STI) were applied on a set of 6 healthy volunteers, based on ECG, PCG and CV pulsation signals. CV pulsation signals were measured on carotide arthery with PPG and LPG sensors. In the first method, EF was calculated from the obtained STI signals, using CV carotide pulsations measured with the PPG sensor, giving EF values in the range from 0.60 to 0.68, with maximal standard deviation of 0.05. In the second method, EF was obtained using CV carotide pulsations measured with LPG sensor, giving EF values in the range from 0.60 to 0.66, with maximal standard deviation 0.06. Calculated values of EF with both methods were in the 0.55 to 0.75 range which corresponds to normal EF range in healthy individuals.