Early Post-Operative Arrhythmias and Their Risk Factors after Total Repair of Tetralogy of Fallot in Pediatric Patients

Background: Conduction disturbances can occur early after total correction of Tetralogy of Fallot (TOF). Some of these arrhythmias and alterations like complete right bundle branch block are permanent, while some others like Junctional Ectopic Tachycardia (JET) are transient. Objective: This study aimed to evaluate the early post-operative arrhythmias and their risk factors among pediatric patients with TOF after surgical total correction. Methods: This retrospective study was conducted on pediatric patients aged six months to 15 years old (52.5% male and 47.5% female) with TOF who had consecutively underwent surgical total correction during 2015 - 2017. Patients with additional concomitant cardiac operations, previous arrhythmias before the surgery, or any co-existing cardiac anomalies as well as those with severe post-operative complications were excluded. All pertinent data and Electrocardiographic (ECG) documents were recorded several times right after the operation to detect arrhythmias and ECG changes and to find any association between the related risk factors and the occurrence of arrhythmias. Results: Out of the 118 TOF patients who underwent total correction, 27% were under the age of one year and 73% were above one year old. Among the patients, 78.5% developed permanent ECG changes, mostly complete right bundle branch block and left anterior or posterior hemiblock. Out of these patients, 8.5% had JET together with other permanent arrhythmias and 8.5% had transient JET solely. Therefore 17% of all patients developed JET and 21.5% had no permanent noticeable ECG changes. The most permanent arrhythmia was right bundle branch block followed by left anterior hemiblock and left posterior hemiblock. These arrhythmias mainly manifesed amongst the patients with lower age and those with severe subvalvar pulmonary stenosis. The results showed a significant relationship between the incidence of JET and use of milrinon after the operation. There was no myocardial ischemia or infarction from injury to aberrant coronary arteries passing over the right ventricular outflow tract. Conclusion: Early post-operative permanent arrhythmias after total TOF repair was probably more common amongst the patients who were below one year old with more severe subvalvar pulmonary stenosis. Nonetheless, the occurrence of transient JET was mostly observed in the patients who were given milrinone as a post-operative inotrope medicine.