Tachyarrhythmia as a Primary Presentation in a Patient with Inborn Error of Metabolism—A Case Report

Background: Neonatal cardiac arrhythmias are common; however, rhythm disturbances as primary presentation of an inborn metabolic disorder are extremely rare. We present a case of a recurrent neonatal tachyarrhythmia in a patient with carnitine–palmitoyltransferase (CPT)-II deficiency.

Method: A 2-day-old female neonate was transferred to our pediatric cardiac intensive care unit with suspected aortic coarctation from an outpatient maternity ward. In transit, the patient presented a tachycardia which required cardiopulmonary resuscitation. On arrival, the ECG displayed a wide QRS complex tachyarrhythmia. Demasking atrial flutter via i.v. adenosine bolus, sinus rhythm was successfully restored by biphasic electric cardioversion. A congenital heart disease was discarded. Neither class Ic nor III antiarrhythmic therapy could successfully suppress recurrent multiform tachyarrhythmias of atrial and ventricular type. As oral feeding was reintroduced, the girl developed hypoketotic hypoglycemia and lactate acidosis. The suspicion of a disorder of long-chain fatty acid oxidation was confirmed by molecular genetic analysis as CPT-II deficiency. With establishment of a high carbohydrate and low fat diet, including supportive carnitine and thiamine substitution, the arrhythmias ceased. The further course was complicated by pulmonary hypertension, sepsis, as well as respiratory, renal, and hepatic failure. After 5 weeks of intensive care, she was transfer to a tertiary metabolic center. Currently the girl is still alive and 6 months old.

Results: Clinical presentations of CPT-II deficiency ranges from a lethal neonatal, over a severe infantile hepatocardiomuscular to a mild myopathic form. Manifestation of the first two is a severe multisystemic disease with liver failure, hypoketotic hypoglycemia, cardiomyopathy, seizures, and death. Arrhythmia may occur.

Conclusion: In newborns of consanguineous parents, presenting with therapy-refractory multiform arrhythmias, the differential diagnosis of an inborn error of metabolism should be taken into consideration.

Publication History

Article published online:
12 February 2022