The Influence of Arrhythmia on the Outcomes of Pediatric Patients with Idiopathic Dilated Cardiomyopathy.

Children diagnosed with dilated cardiomyopathy (DCM) are at an increased risk of developing arrhythmias, which can significantly affect their overall prognosis. However, the implantation and effectiveness of implantable cardioverter-defibrillators (ICDs) pose challenges in the pediatric population. Therefore, it is crucial to determine the prevalence of arrhythmia-related death in pediatric patients with DCM. This study investigated the correlation between arrhythmias and mortality in pediatric patients with DCM. This retrospective cohort study examined children with idiopathic DCM referred to Rajaie Cardiovascular, Medical, and Research Institute in Tehran, Iran, from 2017 to 2023. All patients underwent a standard 12-lead electrocardiogram, 24-h Holter monitoring, cardiac magnetic resonance imaging, and echocardiography. Patient outcomes, including death, heart transplantation, and survival, were evaluated within one year of Holter monitoring. A total of 178 children (79 males) with a mean age of 83.06 ± 56.41 months were included in the study. Overall, 72 deaths (40.4%) and 46 heart transplants (25.8%) were recorded and 60 patients (33.7%) survived. There was no significant association between patients' outcomes with ventricular arrhythmias, late gadolinium enhancement, corrected QT interval, and QRS interval prolongation; however, a significantly higher proportion of dead patients had abnormal heart rate variability (P = 0.034). Heart failure was the leading cause of death, with ventricular arrhythmia accounting for two out of 72 deaths. Both cases of ventricular arrhythmia were associated with severe cardiac dysfunction. Arrhythmia-related mortality is rare in children with idiopathic DCM, with severe heart failure being the primary cause of death in this population. Life-threatening arrhythmias primarily occur in DCM children with more compromised cardiac function.