[Clinical classification and surgical treatment of cor triatriatum]

Twenty-one patients (age 35 days to 39 years) with cor triatriatum were treated surgically over a 17 year period at our institute. We define cor triatriatum as a congenital heart anomaly with the presence of an abnormal diaphragm that subdivides the left atrium into an accessory and a true left atrial chambers and that has "direct" hemodynamic communication between an accessory and a true left atrial chambers through one or more fenestration irrespective of accompaniment of an atrial septal defect or a partial anomalous pulmonary venous connection. By contrast with our findings of the hearts with cor triatriatum, every representative classification, such as Lucas-Schmidt's one, had some lack or duplication of the addressed types respectively. So we presented a clinical classification of cor triatriatum as follows: type I is the classical form with intact atrial septum, type IIa has an ASD between an accessory and a right atrial chambers, type IIb has an ASD between a right and a true left atrial chambers, and type IIc is a complexed form that has both communications of IIa's and IIb's. Of 14 typical cor triatriatum without isomerism nor other major complexed anomalies, 7 cases belonged to type I, and IIa 4, IIb 2, IIc 1 respectively. Of 7 so-called atypical cases, 5 cases belonged to type IIc and the rest two were unclassified complexed forms. Characteristically all of atypical cases had persistent left superior vena cava in common. 17 patients underwent total corrections and the rest 4 cases with single right ventricles underwent palliative operations for Fontan procedure in the near future. Transaccessory chamber approach for type I and IIb as the first choice provided ample exposure for complete excision of the obstructing membrane. Trans-right atrial approach were employed for closure of ASDs or for the other intraatrial partitions. Incision of the atrial septum should be avoided to prevent postoperative supraventricular arrhythmias if possible. There were no surgical death nor late death over 6 years follow-up period on the average. There existed some atypical cases that seemed very difficult to make differential diagnoses preoperatively, so careful surgical investigations into intraatrial anatomy should be made to perform proper corrections especially in the atypical cases.