Author Contributions: Drs Gould and Krahn had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Gould, Krahn.
Acquisition of data: Gould, Krahn.
Analysis and interpretation of data: Gould, Krahn.
Drafting of the manuscript: Gould, Krahn.
Critical revision of the manuscript for important intellectual content: Gould, Krahn.
Statistical analysis: Gould, Krahn.
Study supervision: Krahn.
Financial Disclosures: Dr Krahn reported receiving consulting fees and research funding from Medtronic and Guidant.
Funding/Support: This study was unfunded and independently performed.
Investigators by Number of Patients Enrolled: Jean Champagne, Quebec Heart Institute, Laval Hospital, Quebec City, Quebec; Doug Cameron, University Health Network, Toronto, Ontario; Stanley Tung, St Paul's Hospital, Vancouver, British Columbia; David Birnie, Ottawa Heart Institute, Ontario; Raymond Yee, George J. Klein, Allan C. Skanes, Lorne J. Gula, London Health Sciences Center, London, Ontario; Derek V. Exner, Libin Cardiovascular Institute of Alberta, Calgary; Ratika Parkash, QEII Health Sciences Centre, Halifax, Nova Scotia; Chris Simpson, Queen's University, Kingston, Ontario; Jeff Healy, Hamilton Health Sciences Center, Hamilton, Ontario; Basilios Petrellis, St Michael's Hospital, Toronto, Ontario; Bernard Thibault, Montreal Heart Institute, Montreal, Quebec; Laurence Sterns, Vancouver Island Health Authority, Victoria, British Columbia; Eugene Crystal, Sunnybrook, Toronto, Ontario; Atul Verma, Southlake Regional Hospital, Newmarket, Ontario; Soori Sivakumaran, Royal Alexander Hospital, Edmonton, Alberta; William Hughes, Peterborough, Ontario; Elizabeth A. Stephenson, The Hospital for Sick Children, Toronto, Ontario.