Though patients with AV nodal reentry are now routinely cured by catheter ablation, the basic mechanism of this disorder is still under debate. The putative mechanism of AV node reentry was first discovered by the elegant work of Gordon Moe. He demonstrated the existence of dual pathways and echo beats in rabbits. Building on these seminal observations, the mechanism of AVNRT has burgeoned to include the possibility of left atrial input into the node. The first curative nonpharmacologic procedures involved surgical dissection around the AV node and the procedure was rapidly supplanted by catheter ablation procedures. The initial ablative procedure targeted the fast pathway, but later observations showed that ablation of the slow pathway was more effective and safer. Cure of AV nodal reentry which is the most common cause of paroxysmal supraventricular tachycardia became possible through the cooperative efforts of anatomists, physiologists, surgeons, and clinical electrophysiologists.