1 Department of Physiology and Pharmacology, Cumming School of Medicine, Calgary, Alberta, Canada; Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada.
2 Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada; Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Calgary, Alberta, Canada. Electronic address: paul.fedak@gmail.com.