Pieter Martens1, Wilfried Mullens2. 1. Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium; Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium. 2. Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium; Doctoral School for Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium. Electronic address: Wilfried.Mullens@zol.be.