1. Gottfried Schatz Research Center, Division of Medical Physics & Biophysics, Medical University of Graz, Austria (J.H.).
2. Department of Cardiology, Maastricht University Medical Centre and Cardiovascular Research Institute Maastricht, Maastricht University, the Netherlands (J.H.).
3. Institute of Pharmacology, West German Heart and Vascular Center, University of Duisburg-Essen, Essen, Germany (D.D.).
4. Department of Integrative Physiology, Baylor College of Medicine, Houston, TX (D.D.).
5. Departments of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Montréal, Quebec, Canada (D.D.).