Case presentation, patient 1: Permanent atrial fibrillation with mitral incompetence requiring a mechanical prosthesis . A 57-year-old man underwent mitral valve repair for myxomatous mitral valve disease 10 years ago. During the past 3 years, he has been in permanent atrial fibrillation (AF) and has been taking warfarin for anticoagulation. He has had moderate residual mitral valve incompetence that has progressed to severe incompetence with associated left ventricular dilatation requiring further mitral surgery. Should intraoperative ablation also be performed to treat the AF? Case presentation, patient 2: Symptomatic idiopathic intermittent AF . A 48-year-old man presented with a 3-year-long history of intermittent AF. During each AF episode, he was not able to work; otherwise, he was in good health and had no other cardiac disease. During the past 12 months, he has twice undergone cardioversion to relieve AF that persisted for >7 days. His rate control with pharmacological therapy was variable but generally satisfactory. Antiarrhythmic drugs (sotalol, amiodarone, and flecainide) were tried unsuccessfully for control of the AF burden. Percutaneous catheter ablation of the pulmonary vein orifices was tried on 2 separate occasions, and the patient experienced freedom from AF for 3 weeks after each procedure before the AF returned. Case presentation, patient 3: Symptomatic intermittent AF due to hypertrophic cardiomyopathy . A 39-year-old woman presented to the emergency department in pulmonary edema associated with AF, with a ventricular response of 140 bpm. Pharmacological rate control was successful, but she remained in congestive cardiac failure. Echocardiography revealed hypertrophic cardiomyopathy. She underwent cardioversion to sinus rhythm, and further echocardiography demonstrated an outflow tract gradient of 50 mm Hg. She was maintained on β-blocker therapy but re-presented on multiple occasions in AF and congestive heart failure, prompting monthly cardioversion. Catheter-based mapping and pulmonary vein isolation were unsuccessful. AF is the most frequently …