1. Arrhythmia Service, Cardiovascular Division; Brigham and Women's Hospital; Boston MA USA
2. Department of Cardiology, Westmead Hospital; University of Sydney; New South Wales Australia
3. Bern University Hospital and University of Bern; Bern Switzerland
4. Montefiore Medical Center, Albert Einstein College of Medicine; Montefiore-Einstein Center for Heart & Vascular Care; Bronx NY USA
5. Liverpool Heart and Chest Hospital; Liverpool UK