The timing of the onset of symptoms in triple atrial heart is related to the size of the septal orifice. In severe cases of septal orifice narrowing, severe pulmonary congestion and shortness of breath can occur shortly after birth, followed by severe pneumonia and congestive heart failure. What are the manifestations of septal orifice narrowing and how to diagnose it? I. Clinical manifestations: the time of appearance of symptoms is related to the size of the septal orifice. In severe cases with small orifices, severe pulmonary congestion and shortness of breath can occur soon after birth, followed by severe pneumonia and congestive heart failure. In cases with larger orifices, the onset of symptoms is later, occurring in early childhood or in children. Cases with large orifices resemble atrial septal defects and may be clinically asymptomatic, living a normal life with only slight shortness of breath after activity. In most cases, a jet systolic and diastolic murmur can be heard at the base of the heart, and sometimes a continuous murmur can be heard due to a high pressure step difference between the proximal and distal ends of the orifice due to the severity of the obstruction, with P2 hyperactivity. However, there may be no murmur. Second, hemodynamic changes depend on the size of the intra-atrial septal orifice and concurrent malformations. The hemodynamics of a single left-sided triatrial heart is similar to mitral stenosis, and in cases where the left septal orifice is only a few millimeters in diameter, it can cause pulmonary venous reflux stasis, pulmonary depression, pulmonary edema, and pulmonary hypertension, complicated by partial abnormal pulmonary venous reflux or a left-to-right shunt if the septal defect is located between the right atrium and the subatria, or a right-to-left shunt if the septal defect is close to the intrinsic atrial cavity. Clinical types: In 1964, Yi Yoshitake combined the classification of Loeffler and Niwayama with clinical synthesis into three types (Figure 1). Type I: No communication between the paratrial and true left atrium, with paratrial traffic through the foramen ovale or with complete abnormal pulmonary venous reflux, and early infant death. Type II: There are one to several small channels between the paratria and the true left atrium, which are subdivided into two subtypes from a clinical-surgical point of view: (1) No communication with the right atrium, with clinical manifestations similar to mitral stenosis symptoms. (2) Connected to the right atrium, with clinical manifestations similar to those of atrial septal defect or complete abnormal pulmonary venous reflux. Type III: A large communication exists between the parasternal atrium and the true left atrium.