Reversible Atrioventricular Block and Junctional Ectopic Tachycardia in Coxsackievirus B3-Induced Fetal–Neonatal Myocarditis without Left Ventricular Dysfunction

We present a case of fetal–neonatal acute myocarditis caused by coxsackievirus B3 infection in a term neonate. The condition manifested as high-grade atrioventricular (A-V) block prenatally. After delivery, various arrhythmias such as high-grade A-V block, ventricular tachycardia, and junctional ectopic tachycardia appeared, and we had difficulty managing these arrhythmias. This is the first report describing a case of acute myocarditis due to coxsackievirus infection presenting with fetal A-V block. This case is also unique in that it is extremely rare that various arrhythmias occur serially in one patient without left ventricular dysfunction.