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

Early diagnosis of the cardiac abnormalities during the pregnancy may reduce the risk of perinatal morbidity and mortality. Doppler ultrasound signals (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). 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. Decomposing the fetal Doppler signal using the swarm intelligence achieved an excellent extraction of the fetal cardiac timing events.