1 Department of Cardiology, Heart Center Cologne, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany.
2 Department of Cardiothoracic Surgery, Heart Center Cologne, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany.
3 Department of Cardiology, St Vincent Hospital Cologne, Cologne, Germany.
4 Department of Cardiology, Heart Center Cologne, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany. Electronic address: [email protected].