Arrhythmia is a prevalent complication of the atriopulmonary Fontan procedure, most commonly macro-reentrant tachycardia within the right atrium as a consequence of long-term morphological and haemodynamic changes coupled with surgical intervention. We describe a patient with a long history of supraventricular arrhythmia following the atriopulmonary Fontan procedure identified as atrioventricular nodal reentry tachycardia at electrophysiological assessment. Despite anatomical and technical difficulties related to right atrial morphological changes and loss of the tricuspid annulus with its associated anatomical landmarks, the arrhythmia was successfully ablated using a combined antegrade and retrograde mapping approach.