1. Division of Cardiology, Department of Medicine Johns Hopkins University, Baltimore, MD (V.V., J.A.C.L.).
2. Department of Genomic Health, Geisinger, Danville, PA (S.G.).
3. Department of Medicine, National Heart, Lung and Blood Institute, Bethesda, MD (C.W.).
4. Department Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN (J.C.).