Echocardiography.
D002648:Child; D002675:Child, Preschool; D003490:Cyanosis; D004452:Echocardiography; D006330:Heart Defects, Congenital / Q000175:diagnosis; D006331:Heart Diseases / Q000175:diagnosis; D006333:Heart Failure / Q000175:diagnosis; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008945:Mitral Valve Prolapse / Q000175:diagnosis; D010490:Pericardial Effusion / Q000175:diagnosis