2. 2: Study population:
A total of 185 neonates were eligible for study enrollment during this period. Subjects were eligible for inclusion if they were born term (37-42 weeks), birth weight above 2.2 kg, normal vital signs and 12-leads ECG for age and normal cardiac structure on echocardiography examination except for hemodynamically insignificant small patent ductus arteriosus or small atrial septal defect /patent foramen ovalle. Exclusion criteria are neonates with significant structural heart lesions or abnormal cardiac rhythm on 12-leads ECG. Seventeen babies were excluded due to presence of significant congenital heart lesion and three babies were excluded due to abnormal electrical cardiac rhythm. (Figure 1). Another 63 patients were excluded due to suboptimal echocardiographic image quality i.e. ECG not connected during the study or missing of any of the required apical views: apical 4-chamber view, apical 3 chamber view and apical 2 chamber view.
Demographic data for the participants were documented and complete transthoracic echocardiography study was done for each of them.