1. From the Center for Molecular Cardiology, Department of Physiology and Cellular Biophysics (S.E.L., X.H.T.W., S.R.R., A.R.M.) and Department of Medicine (S.-X.D., Z.C., D.W.L.), Columbia University College of Physicians and Surgeons, New York, NY, and Department of Medicine (P.J.L., K.K., H.S.), University of Helsinki, Finland.