Division of Cardiology, Department of Medicine, University of Ottawa Heart Institute, Ottawa, Ontario, Canada; Division of Nuclear Medicine, Medical Imaging Department, Centre Hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada. Division of Cardiology, Department of Medicine, University of Ottawa Heart Institute, Ottawa, Ontario, Canada. Division of Nuclear Medicine, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada. Division of Cardiology, Department of Medicine, University of Ottawa Heart Institute, Ottawa, Ontario, Canada. Electronic address: dbirnie@ottawaheart.ca.