1 Departments of Cardiology and Physiology, Cardiovascular Research Institute Maastricht (CARIM), P.O. Box 616, 6200 MD Maastricht, The Netherlands.
2 Departments of Cardiology and Physiology, Cardiovascular Research Institute Maastricht (CARIM), P.O. Box 616, 6200 MD Maastricht, The Netherlands. Electronic address: frits.prinzen@maastrichtuniversity.nl.