The patient has paroxysmal atrial fibrillation who presented to the Hospital for electrophysiologic study and catheter ablation. Patient underwent cryoablation of the pulmonary veins. The procedure was uncomplicated. Patient was discharged the next day. The inpatient hospital stay was not medically necessary. For patients undergoing AF ablation, the usual length of stay, for those without procedural complications, is approximately one day, and observation status is standard of care. The hospitalization could have been handled at a lower level of care. In addition, per Milliman guidelines electrophysiologic (EP) testing and catheter ablation are ambulatory procedures. Inpatient admission can be considered for cases of hemodynamically unstable arrhythmia, procedural complications or unstable comorbid condition. None of these conditions apply in this case. The health plan's determination is upheld in whole.