linical cardiac electrophysiology has evolved rapidly over the past several decades, allowing wide-ranging therapeutics to improve the lives of millions of patients. 1 The progression from physiology-based investigations to large, randomized trials of new drugs and devices has allowed clinicians to treat patients with greater confidence and an increasing sense that interventions are evidence-based. 2,3 Approaches to national health care reform have applauded this trend and the increasing authority and rigor of national treatment guidelines, with many leaders calling for greater adherence to evidence and guidelines alike. 4 -9 However, the nuances of the published literature may be lost in translation to patient care or obscured by formal recommendations, which become rapidly ingrained in current practice and the training of new clinicians. 3 Trainees, in particular, may never question the genesis of these recommendations, and thus fail to appreciate the underpinnings of some of the most closely held views in clinical medicine. This article examines the hazards of this phenomenon in clinical arrhythmia management. We ask 3 questions, considered by many to be already settled by the existing evidence and forceful recommendations. We propose that considering these questions more closely illustrates areas in need of further debate and investigation and the importance of preserving critical thinking and clinical judgment.