Pharmacological resynchronisation with flecainide in an infant with Ebstein anomaly and Wolff-Parkinson-White pattern: a case report

Conduction abnormalities are frequently encountered in patients with Ebstein anomaly. The following case describes the safe use of flecainide in an infant with accessory-pathway mediated left ventricular dysfunction in the setting of Ebstein anomaly.

An infant with an antenatal diagnosis of Ebstein anomaly developed progressive left ventricular dilatation and dysfunction over the first 2 months of life. ECG demonstrated persistent Wolff-Parkinson-White pattern with delta-wave polarity suggesting a right-sided septal accessory pathway. In the absence of SVT, accessory-pathway mediated dyssynchrony was suspected as the cause for left ventricular dilatation and dysfunction. He was commenced on flecainide which successfully blocked antegrade conduction via the accessory pathway resulting in a reduction in left ventricular volume and improvement in left ventricular systolic function. He remains asymptomatic at 12 months of age.

There is a known association between Ebstein anomaly and Wolff-Parkinson-White pattern. Right-sided septal accessory pathways can cause cardiomyopathy secondary to dyssynchronous left ventricular contraction. In patients who are unsuitable for accessory pathway ablation, flecainide can be used to block antegrade conduction via the accessory pathway resulting in improved left ventricular function, which was successful on this occasion.