title: Reply to Collins and Le Manach.
authors.affiliation: Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Kieser
authors.affiliation: Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Sarah Rose
authors.affiliation: Department of Thoracic Surgery, Erasmus Medical Centre, Rotterdam, Netherlands.
authors.forename: Stuart
authors.initials: S
authors.lastname: Head