Abstract 3082: Cardiac Arrest in a 22 Year Old Postpartum Female With Carnitine Deficiency
A 22 year old female, ten weeks postpartum, whose baby had been diagnosed with carnitine deficiency on newborn screening, developed syncope with ventricular fibrillation. Bystander CPR was promptly instituted, and defibrillation was accomplished 20 minutes later by EMS. Upon arrival to hospital, she was intubated and unresponsive. Physical exam showed blood pressure 98/62; heart rate 121 bpm; left ventricular S3; clear lungs; and warm legs without edema. Electrocardiogram showed sinus tachycardia at 100 bpm, early repolarization, and ventricular premature beats in quadrigeminy. Induced hypothermia to 33.5 degrees Celsius was initiated, and low-dose intravenous metoprolol was administered. Laboratory testing revealed normal CBC, cardiac enzymes, electrolytes, TSH, and toxicology screen. Echocardiogram showed normal sized cardiac chambers, global left ventricular hypokinesia, and ejection fraction 25%. Differential diagnosis included postpartum cardiomyopathy, idiopathic ventricular fibrillation with early repolarization, and carnitine deficiency-induced cardiomyopathy. Prophy-lactic L-carnitine 1.5 grams every 4 hours was administered, and subsequently a low serum free carnitine level of <5 uM/L was confirmed. Cardiac magnetic resonance imaging five days later showed complete recovery of left ventricular function without discernable intramyocardial fat accumulation. Myocardial biopsy showed cytoplasmic lipid droplets and atypical mitochon-dria consistent with carnitine deficiency. Genetic testing confirmed the diagnosis with three point mutations in the SLC22A5 gene, which encodes the OCTN2 carnitine transporter. An implantable cardioverter-defibrillator was installed, and the patient was discharged on oral L-carnitine and medium chain fatty acid supplements. Neurocognitive function recovered fully. Primary systemic carnitine deficiency is a rare, autosomal recessive, treatable cause of cardiomyopathy and ventricular arrhythmia.