1024: Cardiac Arrest in a Healthy Child: Unmasking Long Qt Syndrome Following Pantoprazole Exposure

Introduction: QT interval prolongation is a known risk factor for ventricular arrhythmias such as Torsades de Pointes. While congenital Long QT Syndrome (LQTS) may remain undiagnosed until triggered, some medications—including proton pump inhibitors like pantoprazole—have been associated with QT prolongation. This case highlights a rare but serious pediatric cardiac arrest revealing latent LQTS after pantoprazole exposure Description: A previously healthy 3-year-old male with mild asthma (on montelukast) was admitted for viral gastroenteritis with moderate dehydration. Labs were normal, and the patient improved with supportive care. Shortly before discharge, IV pantoprazole was given for gastric protection. Within one hour, the child developed acute cyanosis, followed by unresponsiveness. CPR was initiated immediately. A shockable rhythm was detected; ROSC was achieved after 22 minutes, including defibrillation. He was intubated and transferred to the PICU, where he remained on epinephrine infusion for 24 hours. EEG showed diffuse reactive slowing; brain MRI was unremarkable. Cardiac biomarkers were elevated, but echocardiography showed normal function. Serial ECGs revealed QTc >500 ms. Family history uncovered multiple unexplained sudden deaths in childhood, raising concern for inherited LQTS. Pantoprazole was considered a potential arrhythmic trigger. The patient recovered fully and was discharged neurologically intact. Discussion: This case underscores the potential for commonly used medications to unmask undiagnosed congenital arrhythmias. The temporal relationship between pantoprazole and cardiac arrest, along with a suggestive family history, highlights the need for medication review and genetic consideration in pediatric critical care. Serial ECGs and family screening were crucial for diagnosis. Clinicians should maintain vigilance regarding QT-prolonging agents, particularly in pediatric patients with unexplained events or concerning family history. Early recognition and multidisciplinary management enabled a favorable outcome in this high-risk case