CDRH has published a new guidance, "Clinical Study Designs for Catheter Ablation Devices for Treatment of Atrial Flutter." It addresses using a randomized clinical trial approach for clinical studies for catheter ablation devices that treat atrial flutter. The first devices of this kind that received PMAs relied on clinical data from single-arm studies, because no devices to treat the condition were approved at the time. But now a randomized trial is an option because there are such devices on the market. The guidance covers background, scope, study design, study endpoints, statistical considerations, sample size, follow-up of study subjects, anticoagulation parameters, investigator selection and training, data collection forms, and study monitoring. -- James G. Dickinson