[Rhythm disorders occurring after surgical closure of the interatrial communication]

A detailed evaluation is presented about the frequency and the type of arrhythmias following the surgical correction of 147 cases of atrial septal defects not associated with other congenital heart malformations. A total of 131 arrhythmias occurred in 84 patients. The nodal and the coronary sinus rhythms are the most frequently encountered after surgery, attaining 53,8% of all arrhythmias, while atrial fibrillation or flutter represented about 22%. The follow-up of these arrhythmias concerned the 3 month period immediately after surgery. After that time 20% of the arrhythmias occurring in the early postoperative period persisted. The frequency of arrhythmias increased with age, was relatively independent of the importance of the left to right shunt, the level of the mean pulmonary artery pressure and the sex of the patients; but statistically increased in patients in whom the correction was made with a patch. The authors concluded that there must exist at least two mechanisms to explain the occurrence of arrhythmias. A first one must be in relation to the surgical manipulation; the second, which is only an hypothesis, stipulates an alteration of the conduction pathways due to the auricular distention or the existence of a congenital anomaly of the conduction pathways.