WPW in a Patient with Hypoplastic Right Ventricle Syndrome

Background: Supraventricular arrhythmias are often seen in patients after Fontan completion, also case reports are suggesting a higher incidence of Wolff-Parkinson-White syndrome in patients with tricuspid atresia.

Method: A 6-year-old patient with known tricuspid atresia and secondary pulmonary atresia was scheduled to undergo an electrophysiological study before Fontan completion due to a preexcitation pattern and history of atrioventricular re-entrant tachycardias (AVRTs). The patient's history included an mBTT shunt as a newborn and a bidirectional, bilateral Glenn-anastomosis at the age of 1 (left) and 3 (right) years.

Results: Preprocedural, we performed a CMR (cardiac magnetic resonance), which revealed minimal forward flow via a perforated membrane into the rudimentary right ventricle located inferior and posterior from the left ventricle. In combination with the preexcitation pattern seen in the ECG, this led to the assumption of an accessory pathway (AP) located in the region of the tricuspid annulus. The electrophysiological (EP) study was performed in sedation with midazolam and propofol. During the EP study only non-sustained atrioventricular re-entrant tachycardia was inducible. The mapping with the 3D mapping system NavX was done during sinus rhythm. The site of earliest ventricular activation was found in the lateral region of the hypoplastic tricuspid annulus. Radiofrequency (RF) ablation at this site eliminated the conduction via the AP and the preexcitation vanished.

Conclusion: We have been able to map and ablate an accessory pathway in a rudimentary right ventricle of a patient with hypoplastic right ventricle syndrome. Ultimately, the pre-procedural CMR helped understand the anatomical circumstances, reduced the procedure time, and increased the procedural safety. Our patient had a tricuspid valve stenosis instead of a classic tricuspid valve atresia, which made the passing of the tricuspid membrane possible during mapping and RF ablation. As suspected beforehand, the AP presented on the right side, which supports the theory that the AP is on the side of the atretic valve. As patients after completion of the cavopulmonary anastomosis have a higher incidence of atrial arrhythmias, there is a greater risk of sudden cardiac death especially in patients with a manifest AP. Therefore, every patient with anatomical or functional single ventricle and preexcitation pattern should undergo an EP study before Fontan completion, as access of the heart will then only be possible via puncture of the TCPC tunnel or a fenestration.

Publication History

Article published online:
28 January 2023