1. St Bartholomew's Hospital , London, UK
2. University of Zurich , Zurich, Switzerland
3. Medtronic , Minneapolis, MN, USA
4. University Hospital Puerta de Hierro—Majadahonda , Madrid, Spain
5. Maastricht University Medical Center , Maastricht, Netherlands
6. Albert Einstein College of Medicine and Montefiore Medical Center , New York, NY, USA