1. Department of Physiology, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec H3G 1Y6, Canada
2. Departamento de Instrumentación Electromecánica, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City 14080, Mexico
3. Heart Rhythm Services, Division of Cardiology, University of British Columbia, Vancouver, British Columbia V6E 1M7, Canada