Snap Shot A 68-year-old female on digoxin presents complaining of lethargy. Introduction Rapid, regular atrial rhythm due to well-defined reentrant circuit in the right atrium Atrial rate 250-350 Ventricular rate 150-225 varies with AV conduction Less common than atrial fibrillation hemodynamic consequences and treatment are similar Presentation Symptoms vary with ventricular rate and conduction ratio through the AV node usually asymptomatic may present with palpitations dizziness syncope lightheadedness Physical exam tachycardic pulse may be diaphoretic Evaluation EKG flutter waves P waves in a saw tooth pattern Differential Multifocal atrial tachycardia, atrial flutter, tachycardia with variable AV block, ventricular tachycardia Treatment Anticoagulation Rate control Digoxin decrease AV conduction slow onset of effects Verapamil Beta blockers Cardioversion If < 48 hours then perform chemical conversion: 1) procainamide 2) sotalol 3) amiodarone electrical cardioversion (shocks of 100-200J followed by 360J) If > 48 hours then anticoagulate with warfarin and electrocardiovert in 3-4 weeks esophageal echocardiogram to rule out left atrial thombi before cardioversion anticoagulate for 4 weeks following cardioversion. Ablation best long-term/definitive treatment Prognosis, Prevention, and Complications Prognosis leads to increased risk of stroke Complications atrial mural thrombi emboli to cerebral vessels causing TIA or CVA