Ablation of Accessory Pathways with Uncommon Electrophysiologic Properties

In rare cases, atrioventricular reentrant arrhythmias are sustained by accessory pathways with peculiar electrophysiologic features that may be related to their specific anatomy. Most of these bundles show decremental nodelike conduction properties and sustain peculiar forms of arrhythmias that require careful differential diagnosis. On the other hand, some pathways do not actively sustain any reentrant circuit and should nevertheless be promptly recognized to avoid unnecessary ablation attempts. Although rare, these variants of accessory pathway should be known to warrant a safe and effective catheter ablation procedure.