1 Faculty of Medical Science, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
2 ICES, Toronto, Ontario, Canada.
3 ICES, Toronto, Ontario, Canada; University of Toronto, the Cardiovascular Division, Department of Medicine, Women's College Hospital, Toronto, Ontario, Canada; Peter Munk Cardiac Centre, Toronto General Hospital, Toronto, Ontario, Canada.
4 Division of Cardiology, Zuckerberg San Francisco General Hospital, and the Department of Medicine, University of California, San Francisco, California, USA. Electronic address: David.Waters@ucsf.edu.