1. From Laval University, Department of Medicine (G.B., V.P., M.C.) and Québec Heart Institute, Laval Hospital, Research Center (G.B., V.P., M.C.), Sainte-Foy, Québec, Canada; Service de Cardiologie, Hôpital Lariboisière (I.D.) and INSERM U523, Institut de Myologie, IFR “Cœur, muscles et vaisseaux” No. 14, Groupe hospitalier Pitié-Salpêtrière (P.G.), Paris, France; and Department of Physiology, McGill University (A.S.), Montreal, Canada.