title: Significance for exercise capacity of some electrocardiographic findings in racehorses.
abstract: Various cardiorespiratory and metabolic indices were assessed during treadmill exercise in Thoroughbred and Standardbred racehorses with T wave changes in 4 or more leads on the electrocardiogram or second-degree atrio-ventricular (AV) block, and in horses that had no abnormalities on clinical examination, resting electrocardiography or upper respiratory tract endoscopy. No significant differences in heart rate, plasma lactate concentration, arterial blood gases, oxygen uptake, run time, peak velocity, or blood and red cell volumes were found between normal horses and horses with T wave changes or second-degree AV block. These results indicate that some electrocardiographic findings that are considered by some clinicians to indicate cardiac dysfunction, may have little effect on exercise capacity.
authors.affiliation: Department of Veterinary Clinical Sciences, University of Sydney, New South Wales.
authors.forename: C M
authors.initials: CM
authors.lastname: King
authors.forename: D L
authors.initials: DL
authors.lastname: Evans
authors.forename: R J
authors.initials: RJ
authors.lastname: Rose
mesh_terms: D000818:Animals; D001810:Blood Volume; D002245:Carbon Dioxide / Q000097:blood; D004562:Electrocardiography / Q000662:veterinary*; D005080:Exercise Test / Q000662:veterinary; D005684:Gait; D006327:Heart Block / Q000503:physiopathology / Q000662:veterinary*; D006339:Heart Rate; D006734:Horse Diseases / Q000503:physiopathology*; D006736:Horses / Q000502:physiology*; D007773:Lactates / Q000097:blood; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011446:Prospective Studies
chemical_list: D007773:Lactates; D002245:Carbon Dioxide; D010100:Oxygen