1. From the Knight Cardiovascular Institute (K.D., N.G., P.J., K.M., I.G.Z., M.R.), Biostatistics and Design Program (M.L.), Oregon Clinical & Translational Research Institute (OCRTI), Oregon Health and Science University, Portland; and Electrophysiology Department, Portland Veterans Affairs Medical Center, OR (P.J., K.M., I.G.Z., M.R.).