1. From the Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD (P.V.J.)
2. BioCardia, Inc, San Carlos, CA (H.J.D.)
3. Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison (A.N.R.)
4. Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison (T.D.C.)
5. Division of Cardiovascular Medicine, University of Florida, Gainesville (C.J.P.).