Heart Rate Variability Discriminates Outcomes After Pediatric Cardiac Arrest

OBJECTIVE: To assess the performance of heart rate variability (HRV) in discriminating death and functional neurologic outcomes in children post-cardiac arrest. DESIGN: Single-center retrospective review of physiologic and clinical data. SETTING: Forty-six-bed PICU. PATIENTS: Children older than 28 days and 18 years old or younger admitted to the PICU after in-hospital or out-of-hospital cardiac arrest between 2013 and 2019. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was all cause in-hospital mortality within 1 week of arrest. Secondary outcomes included functional neurologic status at hospital discharge by Pediatric Cerebral Performance Category (PCPC) scores, and the presence of poor prognostic findings on transcranial Doppler and/or electroencephalography within 72 hours of ICU admission. Seventy-five patients were included, with a 1-week in-hospital mortality rate of 23% (17 patients). Median integer HRV (mHRVi) in the first 12 hours of PICU admission was significantly lower in patients who experienced 1-week in-hospital mortality ( p < 0.01). The 12-hour mHRVi had an area under the receiver operating characteristic of 0.74 (95% CI, 0.61-0.86) with an area under the precision recall curves of 0.42 for discriminating 1-week in-hospital mortality, and remained statistically significant after adjusting for age, location of arrest, illness severity by Pediatric Risk of Mortality III scoring, and a patients maximum vasoactive-inotropic score ( p = 0.034). There was also a significant association seen between lower 12-hour mHRVi and poor neurologic outcomes by PCPC scoring (odds ratio 0.26 [95% CI, 0.076-0.72]; p = 0.01). CONCLUSIONS: Lower mHRVi over the first 12 hours of PICU admission after cardiac arrest demonstrated moderate discrimination for 1-week in-hospital mortality and poor neurologic outcomes. These findings suggest that mHRVi may serve as a helpful adjunct within multimodal prognostication frameworks, though further validation in larger, diverse cohorts is required before clinical application.