Yolanda Macías1, Marcos C de Almeida2, Justin T Tretter3, Robert H Anderson4, Diane E Spicer5, Timothy J Mohun6, Damián Sánchez-Quintana7, Jerónimo Farré8, Eduardo Back Sternick9. 1. Department of Medical and Surgical Therapeutics, Veterinary Faculty, University of Extremadura, Cáceres, Spain. 2. Department of Genetics and Morphology, Brasilia's University, Campus Asa Norte, Brasilia, Brazil. 3. Department of Pediatrics, Heart Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA. 4. Biosciences Institute, Newcastle University, Newcastle-upon-Tyne, UK. 5. Congenital Heart Center, University of Florida, Gainesville, FL, USA. 6. The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK. 7. Department of Human Anatomy and Cell Biology, Faculty of Medicine, University of Extremadura, Badajoz, Spain. 8. Fundación Jiménez Díaz University Hospital, Institute of Biomedical Research, Madrid, Spain. 9. Arrhythmia and Electrophysiology Unit, Biocor Institute, Nova Lima, Minas Gerais, Brazil.
Abstract
AIMS: The arrangement of the conduction axis is markedly different in various mammalian species. Knowledge of such variation may serve to question the validity of using animals as prospective models for design of systems for clinical use. METHODS AND RESULTS: We compared the arrangement of the atrioventricular conduction axis in human, murine, canine, porcine, and bovine hearts, examining serially sectioned datasets from 20 human, 16 murine, 3 porcine, 5 canine, and 1 bovine hearts. We also analysed computed tomographic datasets obtained from bovines and one human heart. Unlike the situation in the human heart, there is no formation of an atrioventricular fibrous membranous septum in the murine, canine, porcine, nor bovine hearts. Canine, porcine, and bovine hearts also lack an infero-septal recess, when defined as a fibrous plate supporting the buttress of the atrial septum. In these species, half of the non-coronary leaflet is directly opposed to the ventricular septal surface. CONCLUSION: There is a long right-sided non-branching component of the axis, which skirts the attachment of the non-coronary sinus of the aortic root. In the bovine heart, moreover, the left bundle branch usually extends intramyocardially as a solitary tape before surfacing and ramifying on the left ventricular septal surface. The difference in the atrioventricular conduction axis between species may influence the anatomical substrates for atrioventricular re-entry tachycardia, as well as providing inferences for assessing the risks of transcatheter implantation of the aortic valve. Further studies are now needed to assess these possibilities. Published on behalf of the European Society of Cardiology. All rights reserved.
AIMS: The arrangement of the conduction axis is markedly different in various mammalian species. Knowledge of such variation may serve to question the validity of using animals as prospective models for design of systems for clinical use. METHODS AND RESULTS: We compared the arrangement of the atrioventricular conduction axis in human, murine, canine, porcine, and bovine hearts, examining serially sectioned datasets from 20 human, 16 murine, 3 porcine, 5 canine, and 1 bovine hearts. We also analysed computed tomographic datasets obtained from bovines and one human heart. Unlike the situation in the human heart, there is no formation of an atrioventricular fibrous membranous septum in the murine, canine, porcine, nor bovine hearts. Canine, porcine, and bovine hearts also lack an infero-septal recess, when defined as a fibrous plate supporting the buttress of the atrial septum. In these species, half of the non-coronary leaflet is directly opposed to the ventricular septal surface. CONCLUSION: There is a long right-sided non-branching component of the axis, which skirts the attachment of the non-coronary sinus of the aortic root. In the bovine heart, moreover, the left bundle branch usually extends intramyocardially as a solitary tape before surfacing and ramifying on the left ventricular septal surface. The difference in the atrioventricular conduction axis between species may influence the anatomical substrates for atrioventricular re-entry tachycardia, as well as providing inferences for assessing the risks of transcatheter implantation of the aortic valve. Further studies are now needed to assess these possibilities. Published on behalf of the European Society of Cardiology. All rights reserved.