Retrograde sharp potential resembling the his-bundle electrogram: is this a case of atrioventricular re-entrant tachycardia involving twin atrioventricular nodes with the anterior node exhibiting only retrograde conduction?

Atypical sites of twin atrioventricular nodes in a rare form of univentricular heart

Twin atrioventricular nodes (AVNs) associated with complex tachycardias has been described in a heart with discordant atrioventricular (AV) connection. The present case had twin AVNs (approximately 3 o'clock and 8 o'clock position) of sole AV annulus with absent right AV connection. It is a first report demonstrated the twin AVNs identified at atypical sites associated with a univentricular heart with single inlet connection.