Left and right cardiac performance in children with small heart syndrome – Analysis with cardiac MRI –

Abstract Background: It has been reported that children who have orthostatic dysregulation (OD) symptoms are more likely to have a small heart. A low cardiac output of the left ventricle (LV) is thought to be the cause of the symptoms. Because the right ventricle (RV) has not been evaluated in past reports, we examined the cardiac activity of both ventricles by cardiac MRI (CMR) Method: We performed CMR in 23 children with small heart syndrome. Next, we divided the subjects into two groups based on the severity of the symptoms of OD The subjects were divided into two groups according to the severity of the OD symptoms (severe group S-group and mild group M-group) according to the guidelines, and the CMR cardiac parameters were compared. Results: Both ventricular volumes were smaller than normal, but the ejection fractions were within normal range. In the comparison of the severity of the OD symptoms,the LV end-diastolic volume, cardiac index, RV stroke volume, and ejection fraction were significantly smaller in the S group. In a simple logistic regression analysis using the severity of the OD symptoms, the LV end-diastolic volume, cardiac index, and RV ejection fraction were statistically significant variables. Conclusions: We could evaluate the RV performance in small heart syndrome using CMR. We found that the RV ejection fraction might contribute to the severity of the OD symptoms.