1. From INSERM Avenir & U252 (J.-S.H., X.J., J.-P.E., G.F.), Department of Pharmacology (J.-S.H.) and Department of Cardiology, Cardiac Arrhythmias Department (R.F., G.F.), Pitié-Salpêtrière University Hospital, Assistance-Publique Hôpitaux de Paris; and Department of Cardiology, Hôpital Européen Georges Pompidou, University Paris 5 (X.J., J.-P.E.), Paris, France.