Very late recurrences after ablation of AVNRT

Very late recurrences after ablation of AVNRT have been reported. Age related alterations of nodal tissues caused by fibrous and fatty tissue infiltration and changes of the sympathovagal influence on the AV node, in turn altering AV nodal conduction and refractoriness, could set the stage for a previously not present substrate for AVNRT. Consequently, the occurrence of AVNRT many years after an ablation procedure may perhaps not always implicate a recurrence but instead an arrhythmia caused by a new substrate.