An Atypical Presentation of a Typical Arrhythmia.

The article describes the case of a 44 year old man with a long history of a narrow complex tachycardia and prior left lateral accessory pathway (LL-AP) ablation presented to the electrophysiology laboratory for a redo supraventricular tachycardia (SVT) ablation procedure. It notes that the case highlights the diagnostic challenge that occurs in case of recurrence of LL-AP in the setting of mitral annular block.