Heart rate variability as an early predictor for children with SARS-CoV-2-associated encephalopathy

Background: Although encephalopathy and encephalitis are uncommon complications of SARS-CoV-2 infection in children, they can lead to significant morbidity and mortality. Therefore, the aim of the study is to assess heart rate variability in children with SARS-CoV-2 infection and determine those at risk of progressing to SARS-CoV-2-associated encephalopathy. Methods: Children with confirmed SARS-CoV-2 infection between September 1, 2022 and December 8, 2023 were prospectively enrolled and divided into encephalopathic and non-encephalopathic groups. The non-encephalopathic group was further classified into mild, moderate, and severe/critical disease groups. One-minute electrocardiography was recorded on the first day of admission. Heart rate variability indices were compared between the encephalopathic and non-encephalopathic groups. Results: A total of 72 children (30 girls [41.7 %] and 42 boys [58.3 %]) with SARS-CoV-2 infection were enrolled, with age ranging from 1 month to 18 years. Of these children, 15 (20.8 %) were classified into the encephalopathic group, and 57 (79.2 %) were classified into the non-encephalopathic group. We compared heart rate variability indices and found that both time domain analysis (SDNNc and RMSSDc) and nonlinear Poincaré plot analysis (SD1/SD2 ratio) were lower in the encephalopathic group and severe/critical disease group than in the mild and moderate severity non-encephalopathic groups. Conclusions: Heart rate variability parameters were significantly lower in the severe/critical disease group and the encephalopathic group compared to the mild to moderate severity groups. The implications of heart rate variability, particularly when considering neurological symptoms, as a predictor of disease progression to encephalopathy require further evaluation.