Objective: To investigate cardiac reserve by using a method based on the relation between cardiac contractility and heart sound in children with ASD before and after intervention.Methods: Children with ASD(n=20)

and ASD with pulmonary hypertension(n = 20)

and normal control(n= 20) were enrolled in this study.The phonocardiograms were recorded for each control subject

each patient with ASD and ASD with pulmonary hypertension at rest before the intervention

one day after the intervention

and 6 months after the intervention by using a cardiac contractility monitor.The first heart sound amplitude(S1)

the second heart sound amplitude(S2)

diastolic(D) and systolic(S) durations were measured with cardiac reserve software.The ratios of S1/S2 and D/S were analysed.Results: Compared with the control

the ratios of S1/S2 and D/S were lower in the ASD before intervention

which were the lowest in the ASD with pulmonary hypertension.The ratios of S1/S2 and D/S were increased after intervention

and more significantly increased 6 months after intervention.Conclusion: The cardiac reserve in children with ASD decreases before intervention

and increases after intervention.