1. Department of Cardiovascular Medicine, Mayo Clinic , 200 First Street SW, Rochester, MN 55905, USA
2. Cardiology Division, National Taiwan University Hospital , Taipei, TW 100, Taiwan
3. Department of anatomic pathology, Mayo Clinic , Rochester, MN 55905, USA
4. Division of Biomedical Statistics and Informatics, Mayo Clinic , Rochester, MN 55905, USA