Postnatal Neonatal Myocardial Adaptation is Associated with Loss of Tolerance to Tachycardia : a 1 Simultaneous Invasive and Noninvasive Assessment

Fetal & Neonatal Cardiology Program, Division of Cardiology and Neonatology, Women’s & Children’s 5 Health Research Institute, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, 6 Alberta Canada. 7 School of Public Health, University of Alberta, Edmonton, Alberta Canada 8 Current Affiliation 9 Department of Pediatrics, Université de Sherbrooke, Sherbrooke, Canada (EFP) 10 Department of Pediatrics, Division of Cardiology, University of Calgary (L M) 11 Correspondence 12 Dr Lisa K Hornberger, 13 Pediatric Cardiology 4C2 Stollery Children’s Hospital, University of Alberta 14 8440 112 Street, Edmonton, Alberta 15 Tel: 7804073355, Fax 7804073954 16 Email: [email protected] 17 Contributions: EFP: Protocol, ethic submission, experimental procedures, data collection and analysis, 18 manuscript. LM: data collection and manuscript. NSK: data collection and manuscript. JYC: supervised 19 protocol, experimental procedures, data collection, and manuscript. PYC: supervised protocol, technical 20 support for experimental procedures, and manuscript. LKH: supervised protocol, data collection, and 21 manuscript. 22 Running Head: Tolerance to tachycardia in the early infancy 23 Articles in PresS. Am J Physiol Heart Circ Physiol (December 30, 2015). doi:10.1152/ajpheart.00595.2015