Arrhythmias and conduction abnormalities in children after repair of tetralogy of Fallot

AIM: To find out types and frequency of cardiac arrhythmias and conduction abnormalities in the group of children who underwent surgery for tetralogy of Fallot (TOF). METHODS: Forty-six pedicatric patients who underwent a complete repair of TOF at the age of 1 to 13 (mean 2.89+/-2.36) were studied Thirty-eight (82.60%) had total correction and 8 (17.40%) had palliative operation first, and total correction afterwards. Twenty-four-hour Holter ECG monitoring was performed in all 46 pediatric patients aged from 1 to 16 yrs (mean 6.48+/-4.04) after surgery as follows: in 1 patient (2.17%) after a year, in 20 patients (43.477%) after 2 to 5 years and in 25 patients (54.34%) after 5 years. Mean age of patients on Holter monitoring was 9.25+/-4.39 (range 4-19). Twenty of them (43.47%) were girls and 28 (56.53%) were boys. All the patients were evaluated by standard methods (clinical signs, clinical findings, ECG before surgery, ECG before Holter monitoring and 2D Doppler echocardiography. RESULTS: Types of heart rhythm found out by Holter monitoring were: sinus nodus dysfunction in 1 child (2.17%), significant premature atrial contraction (PAC) in 8 (17.39%), supraventricular paroxysmal tachycardia in 3 (6.535), transient nodal rhythm in 2 (4.34%), premature ventricular contraction (PVC) Lown grade 1-III in 9 (19.56%) and Lown grade IV in 2 (4.34), atrioventricular (AV) block grade I in 2, right bundle branch block (RBBB) in all 46 (100%) and RBBB + left anterior hemiblock (LAH) in 4 (8.96%). There was no presence of atrial flutter, ventricular tachycardia or complete A V block. None of them experienced sudden death. Using cross procedure statistical methods, it was found that all the patients with PVC had right ventricular dilatation. There was no relation of other types of arrhythmia found on Holter monitoring to the other parameters from echocardiography, neither to the other standard methods. Children did not need the pace-maker, but 36.95% of the them required antiarrhythmic drugs. CONCLUSION: Twenty-four hour Holter ECG is a noninvasive and very sensitive method for discovering heart rhythm disturbances in children after the repair of tetralogy of Fallot, especially in asymptomatic patients. The patients after the repair of this congenital heart disease needed a long-term follow-up for early recognition of serious heart rhythm disturbances and their treatment.