1. Department of Cardiology, University Medical Center Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands
2. Department of Cardiology, Thorax Center, Erasmus University Medical Center, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands
3. Department of Radiology, University Medical Center Groningen, 9700 RB Groningen, The Netherlands