TY - JOUR
T1 - Differences in the electrocardiographic QT interval of various breeds of athletic horses during rest and exercise
AU - Pedersen, Philip Juul
AU - Karlsson, Madeleine
AU - Madsen, Mette Flethøj
AU - Trachsel, Dagmar Senta
AU - Kanters, Jørgen K.
AU - Klærke, Dan Arne
AU - Buhl, Rikke
N1 - Copyright © 2016 Elsevier B.V. All rights reserved.
PY - 2016/9/1
Y1 - 2016/9/1
N2 - OBJECTIVES: Quantitative measurements of cardiac repolarization, defined as the electrocardiographic QT interval, have important diagnostic implications in humans, as irregularities can trigger potentially fatal ventricular tachyarrhythmia. In both humans and horses, cardiac repolarization is influenced to some extent by heart rate, age, body weight (BW), sex, autonomic tone, and environment. In horses, there is substantial inter-breed variation in size and training, and the aims of this study were therefore to determine the best model describing the QT to RR relationship in breeds of various athletic horses and to test for differences in the QT interval.ANIMALS: Ten Icelandic horses, 10 Arabian horses, 10 Thoroughbreds, 10 Standardbreds, six Coldblood trotters, 10 Warmbloods (dressage) and 10 Warmbloods (show jumping). All horses were geldings.METHODS: QT intervals were measured from resting to peak exercise level and plotted against RR intervals. Data points were fitted with relevant regression models, and the effect of breed, BW, and estimated exercise intensity was examined.RESULTS: For all breeds in this study, the QT interval was best described as a function of RR by the piecewise linear regression model. The breed of horse had a significant effect on the model. There was no systematic effect of BW or estimated exercise intensity, but a high inter-horse variability was observed.CONCLUSIONS: The equine QT interval should preferably be corrected for heart rate according to breed. In addition, the results indicate that equine studies of the QT interval must be designed to eliminate the influence of a large inter-horse variation.
AB - OBJECTIVES: Quantitative measurements of cardiac repolarization, defined as the electrocardiographic QT interval, have important diagnostic implications in humans, as irregularities can trigger potentially fatal ventricular tachyarrhythmia. In both humans and horses, cardiac repolarization is influenced to some extent by heart rate, age, body weight (BW), sex, autonomic tone, and environment. In horses, there is substantial inter-breed variation in size and training, and the aims of this study were therefore to determine the best model describing the QT to RR relationship in breeds of various athletic horses and to test for differences in the QT interval.ANIMALS: Ten Icelandic horses, 10 Arabian horses, 10 Thoroughbreds, 10 Standardbreds, six Coldblood trotters, 10 Warmbloods (dressage) and 10 Warmbloods (show jumping). All horses were geldings.METHODS: QT intervals were measured from resting to peak exercise level and plotted against RR intervals. Data points were fitted with relevant regression models, and the effect of breed, BW, and estimated exercise intensity was examined.RESULTS: For all breeds in this study, the QT interval was best described as a function of RR by the piecewise linear regression model. The breed of horse had a significant effect on the model. There was no systematic effect of BW or estimated exercise intensity, but a high inter-horse variability was observed.CONCLUSIONS: The equine QT interval should preferably be corrected for heart rate according to breed. In addition, the results indicate that equine studies of the QT interval must be designed to eliminate the influence of a large inter-horse variation.
KW - Journal Article
U2 - 10.1016/j.jvc.2016.02.002
DO - 10.1016/j.jvc.2016.02.002
M3 - Journal article
C2 - 27068842
SN - 1760-2734
VL - 18
SP - 255
EP - 264
JO - Journal of Veterinary Cardiology
JF - Journal of Veterinary Cardiology
IS - 3
ER -