1. Department of Physiology and Biophysics, Dalhousie University, 5850 College St, Halifax, NS B3H 4R2, Canada
2. Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical School of the University of Freiburg, Elsaesser Str 2Q, 79110 Freiburg, Germany
3. National Heart and Lung Institute, Imperial College London, The Magdi Yacoub Institute, Hill End Road, UB9 6JH London, UK