Arrhythmias in repaired pediatric and adolescent Fallot tetralogy, correlation with cardiac MRI parameters

Background: Tetralogy of Fallot (TOF) is a common congenital cyanotic heart disease in which arrhythmias could develop even after successful operative repair. Pulmonary regurgitation and right ventricular dilatation develop in many cases. The relation between arrhythmias and right ventricular dilatation is not established. Our aim is to assess the relation in between the degree of right ventricular volume affection and the severity of the pulmonary regurgitation, associated arrhythmias and the need for pulmonary valve repair in Egyptian pediatric and adolescent cases after successful TOF repair. Results: A cross sectional descriptive study was conducted on 32 cases after successful surgical repair. Transthoracic Doppler echocardiography, 24 h Holter monitoring and cardiac MRI for assessment of pulmonary regurgitation fraction (PRF), ventricular volumes and function were measured. Cases were classified according to right ventricular end diastolic volume index (RVEDVI) into 2 groups with cut off value 150 ml/m. Mean age of the studied cases was (12.96 ± 3.384) years, mean age at time of surgical repair was (34.23 ± 22.1) months, and mean duration postoperatively was (121.72 ± 41.028) months. Eighteen cases (56%) had RVEDVI ≥ 150 ml/m, PRF was significantly higher in cases with increased RVEDVI (p value 0.007), with positive significant correlation between RVEDVI and PRF (p value = 0.0001, r = 0.61). Arrhythmias were detected in 18 cases (56%), the most common of which was infrequent supraventricular ectopy. No significant difference in incidence of arrhythmias between the 2 groups (p value = 1) with also no significant correlation between arrhythmias and increased RVEDVI (p value = 0.76, r = 0.05). No difference between cases with and without arrhythmias regarding RVEDVI (p value = 0.56) or PRF (p value = 0.5). Conclusion: Holter detected arrhythmias after successful surgical repair of TOF were significantly associated with increased postoperative duration but not with PRF or RVEDVI.