This document discusses atrioventricular nodal reentrant tachycardia (AVNRT), which accounts for about 2/3 of paroxysmal supraventricular tachycardia cases. It involves a dual pathway in the AV node allowing for a reentrant circuit. Management in the acute setting includes vagal maneuvers, adenosine, or calcium channel blockers, while long term management may involve medications like digoxin, beta blockers, or calcium channel blockers. Catheter ablation has a 95% success rate but a 1% risk of AV block, and is recommended for severe, frequent, or medication-resistant cases.