Identification of Fetal Cardiac Timing Events by Swarm Decomposition of Doppler Cardiogram Signal

Saeed Alnuaimi1, Shihab Jimaa1, Yoshitaka Kimura2, Georgios Apostolidis3, Leontios Hadjileontiadis1, Ahsan Khandoker1
1Khalifa university, 2Tohoku University, 3Aristotle University of Thessaloniki


Abstract

Early diagnosis of the cardiac abnormalities during the pregnancy may reduce the risk of perinatal morbidity and mortality. The information provided from the fetal cardiac assessments can be used for early diagnosis of fetal cardiac diseases, such as various types of Congenital Heart Diseases (CHDs). Doppler ultrasound (DUS), which is commonly used for monitoring the fetal heart rate, can also be used for identifying the event timing of fetal cardiac valve motions. In this paper, we propose a non-invasive technique to identify the fetal cardiac timing events on the basis of analysis of fetal DUS (5 normal subjects, in both early and late gestational ages). We proposed using the swarm decomposition technique which enabled the frequency contents of the Doppler signals to be linked to the opening and closing of the heart's valves (aortic and mitral). This decomposition method is based on properly parameterizing swarm filtering, that generates oscillatory components (OCs) from a multi-component input signal. Decomposing the fetal Doppler signal using the swarm intelligence achieved an excellent extraction of the fetal cardiac timing events. In the early gestational age, the time intervals from R peak of fetal ECG to opening and closing of aortic valve were found to be 59.4±1.9 ms and 218.8±2.4 ms respectively and in the late gestational age 65.4±10 ms and 218.1±3.4 ms respectively. The rest of the identified timing were mentioned in the results and discussion section. The results show that by applying the swarm decomposition, the component which is linked to valve movements is practically separated, and its peaks which correspond to the cardiac events can be discriminated. The main advantage of the proposed method is that it allows the efficient decomposition of a signal into a set of components that preserve physical meaning, likewise other decomposition techniques such as Empirical mode decomposition.