1 North West Thames Regional Genetics Service, St Mark's and Northwick Park Hospitals, London, UK.
2 Center for Inherited Cardiovascular Diseases, WellSpan Health, Lancaster, PA, USA; Barts Heart Centre, St Bartholomew's Hospital, Barts Health NHS Trust, London, West Smithfield, EC1A 7BE, UK; Cardiac Electrophysiology, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, PA, USA; Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA. Electronic address: anwar.chahal@pennmedicine.upenn.edu.