1 Divisions of Cardiac Surgery, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada. Electronic address: [email protected].
2 Health Science Center, St. John's, Newfoundland, Canada.
3 Division of Cardiac Surgery, McMaster University, Canada.
4 Department of Surgery, Max Rady College of Medicine, University of Manitoba & Cardiac Sciences Program, St. Boniface Hospital, Winnipeg, Manitoba, Canada.