(765) Averted Sudden Cardiac Death and Survival to Transplant in a Child With Histiocytoid Cardiomyopathy

Introduction: Histiocytoid cardiomyopathy is a rare genetic disorder (~100 cases reported) primarily affecting females < 2 years of age and manifesting with recalcitrant arrhythmias, dilated cardiomyopathy, or sudden death. We describe the case of an infant presenting after protracted out-of-hospital cardiac arrest who was diagnosed with histiocytoid cardiomyopathy and survived to successful orthotopic heart transplant.

Description: A 24 day-old female infant presented after arrest at home and underwent >2 hours of CPR with cannulation to VA ECMO. Initial echocardiograms revealed severely depressed biventricular function and LV noncompaction with hypertrophied myocardium. During her 19-day VA ECMO course, she had multiple episodes of torsades de pointes including persistent bradycardia precipitating torsades, requiring placement of temporary pacing wires. She had four additional episodes of cardiac arrest due to torsades requiring CPR +/- defibrillation after decannulation. Whole genome sequencing identified a variant in gene NDUFB11, which has been associated with Linear Skin Defects with Multiple Congenital Anomalies with the cardiac manifestation of histiocytoid cardiomyopathy and malignant arrhythmias. She was maintained on milrinone, mexiletine and propranolol through orthotopic heart transplant at 6 months of age. Hers was the first reported infant donation after cardiac death (DCD) heart transplantation in the United States using normothermic regional perfusion (NRP) and distant transport. Pathology of her explanted heart was consistent with histiocytoid cardiomyopathy.

Discussion: Current national data reflects only 4.9% survival to discharge in infants with out-of-hospital cardiac arrest, yet this patient survived with minimal functional deficit despite nearly 3 hours of initial resuscitation time. Her case supports the efficacy of high-quality CPR at all stages of resuscitation, use of ECPR/ECMO despite prolonged arrest when evidence of preserved neurologic function exists, prompt genetic testing to establish a diagnosis, and early listing for cardiac transplantation despite known a genetic disorder, especially as advances in DCD via NRP protocols increase the donor pool for infants and allow more opportunity for long-term survival.