Atrioventricular nodal tachycardia (AVNRT) is one of the most common supra ventricular tachycardias (SVT) that we find during electrophysiology studies. Fifteen to thirty percent of the population has “dual AV-node physiology.” Most day-to-day conduction is from “fast” AV node pathway. Patients with “dual AV node physiology” may occasional use the “slow” AV node pathway and this can set up the reentrant arrhythmia.