SAN FRANCISCO — The 62nd Annual Scientific Session of the American College of Cardiology (ACC; Bethesda, Maryland) kicked off here early on Saturday morning with a new and surprising turn in a series of unusual events that have surrounded the Prospective Randomized Evaluation of the Watchman LAA Closure Device in Patients With Atrial Fibrillation Versus Long Term Warfarin Therapy (PREVAIL) trial.