1. Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Osaka 564-8565, Japan
2. Department of Cardiovascular Medicine, Shinshu University School of Medicine, Nagano 390-8621, Japan
3. Department of Cardiology, University Hospital of Larissa, 41110 Larissa, Greece
4. Department of Cardiothoracic Surgery, University of Thessaly, Biopolis, 41110 Larissa, Greece