... less. Atrial Septal Defect Closure/Occluder, Ventricular Septal Defect (VSD)Occluder , Patent Ductus Arteriosus (PDA) OccluderTechnical principles The ... equal to 3 years.2) Patients are diagnosed as VSD by clinical diagnosis, electrocardiogram, chest film or transthoracic ... listed below:A: Perimembranous VSD:a, Simple VSD has hemodynamic effects with heart;b, VSD with distance between upper edge ...