Introduction: Ventricular septal defect (VSD) is the most frequent congenital heart disease with an inci-dence of almost 20% of all congenital cardiac disease. Complete heart block (CHB) after surgical closure of ventricular septal defect is a rare complication with an incidence that ranges between 1-3%. In most cases (97%), postoperative CHB is transient, typically resol-ving within 7-14 days after surgery, but if it develops after months or years after surgery, it is consider to be late onset. If the AV block persists more than 7 days it is considered to be permanent and has the indication for implantation of a pacemaker.

Methods: We present a case of a 4-year-old girl diagno-sed at 6 months with perimembranous VSD.

Results: At the age of 2 she underwent a surgical repair of the VSD. In the immediate postoperative period, she developed early trainsient CHB. She returned to sinus rhythm after 3 days of temporary pacing. During the follow-up, the patient had normal sinus rhythm for 2 years, but at the age of 4, she was found to have CHB with a variable heart rate at about 45 bpm. The diagno-se was also confirmed by her Holter monitor, therefo-re she underwent permanent pacemaker implantation with ventricular pacing (VVI mode).

Conclusions: CHB is a rare, but an important compli-cation of pediatric heart surgeries. A high number of patients with early AV block recover shortly after the procedure spontaneously or with temporary pacing. But because of the risk of late developing CHB, pati-ents who underwent surgical repair of the VSD must be followed carefully for life.