Arrhythmia-Induced Cardiomyopathy Presented Cardiogenic Shock Caused by Multifocal Atrial Tachycardia in a 4-Month-Old Boy

Abstract

Multifocal atrial tachycardia (MAT) is generally diagnosed in infants under one year of age; a few of these infants may also present with arrhythmia-induced cardiomyopathy. We report the case of 4-month-old boy diagnosed with cardiogenic shock secondary to MAT who responded to antiarrhythmic medications. e child was delivered by caesarean section at gestational age of 36 weeks due to fetal distress; his birth weight was 2,362 g. He was referred to our hospital at four months of age with chief complaints of poor feeding and tachyarrhythmias detected during a previous examination. A 12-lead electrocardiogram (ECG) revealed a narrow QRS complex and irregular tachycardia at a rate of 200‒240 beats per minute, leading to the diagnosis of MAT. Echocardiography revealed severe functional decline, including an 11% shortening fraction (SF) and a dilated le ventricle. Amiodarone (5 mg/kg injection) was administered in an attempt to normalize the atrial tachycardia; this resulted in a substantial drop in blood pressure. e patient was intubated and provided with inotropic support, including dopamine and milrinone. Landiolol (10 μg/kg/min by continuous infusion) and oral aprindine (1.5 mg/kg/day) were initiated on hospital day 8. e frequency of tachycardia decreased and cardiac function gradually recovered over a period of 2‒3 weeks. e patient was discharged on hospital day 43 with improved cardiac function and a SF of 30%. Results from a follow-up visit revealed the cardiac function had returned to near-normal with no recurrence of MAT. We conclude that it is critical to control MAT in pediatric patients with arrhythmia-induced cardiomyopathy.