A novel mechanism of sudden infant death syndrome during atrioventricular reentrant tachycardia: a case report.

Background: Although orthodromic atrioventricular reentrant tachycardia (AVRT) using retrograde conduction through an accessory pathway (AP) is a common manifestation of Wolff-Parkinson-White (WPW) syndrome, a rare yet critical consequence is sudden cardiac arrest in a few patients. This fatal event used to be reported as a result of rapid atrioventricular conduction of atrial fibrillation via an AP.

Case Summary: A 3-month-old infant with WPW syndrome had AVRT accompanied by global cardiac ischaemia, apparently caused by a rapid ventricular rate itself that degenerated into ventricular fibrillation during the AVRT.

Discussion: Our case suggested that orthodromic AVRT may be sufficient to cause WPW-related sudden cardiac death (SCD) or sudden infant death syndrome via fatal ischaemia and ventricular arrhythmias even when the effective refractory period of an antegrade AP conduction is long or even when an antegrade AP is not present. It is possible that an AP ablation in those who have a history of a fast orthodromic AVRT would be useful to prevent SCD in addition to symptom control.