1. Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna, Vienna, Austria
2. Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
3. Departments of Medicine, Clinical Pharmacology, Pharmacology, and Neurology, Vanderbilt Autonomic Dysfunction Center, Nashville, TN, USA
4. Core Facilities, Medical University of Vienna, Vienna, Austria
5. Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria