FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Journal of veterinary internal medicine2023; 37(6); 2573-2583; doi: 10.1111/jvim.16878

Associations between postrace atrial fibrillation and measures of performance, racing history and airway disease in horses.

Abstract: Atrial fibrillation (AF) is the most common performance limiting arrhythmia in racehorses. High dose exercise and airway disease promote AF in humans. Few studies have investigated epidemiological factors associated with AF in horses. Objective: Explore variables relating to performance, exercise volume and postrace endoscopic findings in horses with AF. Methods: A total of 164 horses with poor race performance and postrace AF were compared to 321 horses with poor performance without AF (PP) and 314 horses performing to expectation (TE). Methods: Horse-level and race-level variables for horses racing in Australia and Hong Kong from 2009 to 2021 were compared using univariable and multivariable logistic regression. Postrace endoscopic exercise-induced pulmonary hemorrhage (EIPH) and tracheal mucus accumulation (TMA) grades for AF and PP horses were compared using chi-squared analysis. Results: Variables that were significant in the multivariable model of AF compared to TE were distance (lengths) behind the winner, (odds ratio [OR]; 95% confidence interval [95% CI], 1.41 [1.32-1.51], P < .0001), cumulative prize money per start before the event (OR [95% CI] 1.02 [1.01-1.03], P = .01) and age (OR [95% CI] 0.72 [0.55-0.92], P = .01). More AF horses had EIPH grade ≥ 3 (23/109; 21.1%) than PP horses (7/213; 3.3%; OR [95%CI] 7.9 [3.3-20.2], P < .0001). Conclusions: Acute race performance was substantially impaired by AF but career earnings before the event were not inferior. Exercise volume did not promote AF. Higher grades of EIPH found in AF horses suggests a mechanistic relationship between these conditions.
© 2023 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.
Get Full Text
Publication Date: 2023-09-23 PubMed ID: 37740606PubMed Central: PMC10658555DOI: 10.1111/jvim.16878Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research investigates the relationship between instances of poor race performance due to atrial fibrillation (AF), a common arrhythmia in racehorses, and factors such as performance variables, exercise levels, and endoscopic findings post-race. The study finds that not only is AF linked significantly to poorer race performance, but also to higher occurrences of exercise-induced pulmonary hemorrhage (EIPH), suggesting a possible physiological correlation between these conditions.

Research Scope and Methodology

  • The study focuses on a total of 164 horses that had poor post-race performance coupled with AF, comparing them with 321 horses with poor performance (PP) without AF and 314 horses that performed as expected (TE).
  • These comparisons were made based on horse-level and race-level variables for horse races in Australia and Hong Kong from 2009 to 2021.
  • A combination of univariable and multivariable logistic regression was used to compare the variables. Additionally, endoscopically diagnosed conditions such as exercise-induced pulmonary hemorrhage (EIPH) and tracheal mucus accumulation (TMA) in horses with AF and poor performance were compared using chi-squared analysis.

Key Findings

  • The multivariable model of AF in comparison to expected performance indicated significant variables like distance behind the winner, cumulative prize money before the event, and the horse’s age.
  • Most horses with AF had a higher grade of EIPH than horses without AF, indicating a potential mechanical relationship between AF and this type of pulmonary hemorrhage.

Conclusions

  • The research concludes that AF significantly impairs race performance in horses. However, it was found that career earnings of these horses before the instance of AF were not lower, suggesting that AF is not necessarily a result of exertion or exercise volume.
  • The higher frequency of EIPH in horses with AF suggests a connection between these conditions, hinting at a physiological correlation that could guide further epidemiological studies in equine health and performance.

Cite This Article

APA
Nath LC, Elliott A, La Gerche A, Weir J, Forbes G, Thomas G, Franklin S. (2023). Associations between postrace atrial fibrillation and measures of performance, racing history and airway disease in horses. J Vet Intern Med, 37(6), 2573-2583. https://doi.org/10.1111/jvim.16878

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 37
Issue: 6
Pages: 2573-2583

Researcher Affiliations

Nath, Laura C
  • University of Adelaide, Roseworthy, Australia.
Elliott, Adrian
  • University of Adelaide, Adelaide, Australia.
La Gerche, Andre
  • Baker Heart and Diabetes Institute, Melbourne, Australia.
Weir, Joe
  • Hong Kong Jockey Club, Hong Kong.
Forbes, Grace
  • Racing Victoria, Melbourne, Australia.
Thomas, Gijo
  • University of Adelaide, Adelaide, Australia.
Franklin, Samantha
  • University of Adelaide, Roseworthy, Australia.

MeSH Terms

  • Humans
  • Horses
  • Animals
  • Atrial Fibrillation / etiology
  • Atrial Fibrillation / veterinary
  • Physical Conditioning, Animal / adverse effects
  • Horse Diseases / etiology
  • Lung Diseases / veterinary
  • Running
  • Hemorrhage / veterinary

Grant Funding

  • Racing Victoria

Conflict of Interest Statement

Authors declare no conflict of interest.

References

This article includes 74 references
  1. Buhl R, Carstensen H, Hesselkilde EZ. Effect of induced chronic atrial fibrillation on exercise performance in Standardbred trotters. J Vet Intern Med 2018;32:1410‐1419.
    pmc: PMC6060327pubmed: 29749082
  2. Slack J, Boston RC, Soma LR, Reef VB. Occurrence of cardiac arrhythmias in Standardbred racehorses. Equine Vet J 2015;47:398‐404.
    pubmed: 24819401
  3. Ohmura H, Hiraga A, Takahashi T, Kai M, Jones JH. Risk factors for atrial fibrillation during racing in slow‐finishing horses. J Am Vet Med Assoc 2003;223:84‐88.
    pubmed: 12839069
  4. Williams RB, Harkins LS, Hammond CJ, Wood JL. Racehorse injuries, clinical problems and fatalities recorded on British racecourses from flat racing and National Hunt racing during 1996, 1997 and 1998. Equine Vet J 2001;33:478‐486.
    pubmed: 11558743
  5. Nath LC, Elliott AD, Weir J, Curl P, Rosanowski SM, Franklin S. Incidence, recurrence, and outcome of postrace atrial fibrillation in thoroughbred horses. J Vet Intern Med 2021;35:1111‐1120.
    pmc: PMC7995445pubmed: 33604980
  6. Holmes JR. Cardiac arrhythmias on the racecourse. Equine Exerc Physiol 1986;2:781‐785.
  7. Rosanowski SM, Chang YM, Stirk AJ, Verheyen KL. Descriptive epidemiology of veterinary events in flat racing thoroughbreds in Great Britain (2000 to 2013). Equine Vet J 2017;49:275‐281.
    pubmed: 27208544
  8. Nath LC, Forbes G, Elliott AD, Tomren V, Ryan A, Franklin SH. Application of an electrocardiography device (iECG) for heart rhythm analysis after exercise in thoroughbred horses. Aust Vet J 2022;100:114‐120.
    pubmed: 34859419
  9. Buhl R, Hesselkilde EM, Carstensen H. Detection of atrial fibrillation with implantable loop recorders in horses. Equine Vet J 2021;53:397‐403.
    pmc: PMC7891449pubmed: 32506470
  10. Massie SL, Bezugley RJ, McDonald KJ. Prevalence of cardiac arrhythmias and RR interval variation in healthy thoroughbred horses during official Chuckwagon races and recovery. Vet J 2021;267:105583.
    pubmed: 33375959
  11. Decloedt A, Schwarzwald CC, De Clercq D. Risk factors for recurrence of atrial fibrillation in horses after cardioversion to sinus rhythm. J Vet Intern Med 2015;29:946‐953.
    pmc: PMC4895430pubmed: 25917409
  12. Vernemmen I, De Clercq D, Decloedt A. Atrial premature depolarisations five days post electrical cardioversion are related to atrial fibrillation recurrence risk in horses. Equine Vet J 2020;52:374‐378.
    pubmed: 31583742
  13. Vernemmen I, Van Steenkiste G, Dufourni A, Decloedt A, Van Loon G. Transvenous electrical cardioversion of atrial fibrillation in horses: horse and procedural factors correlated with success and recurrence. J Vet Intern Med 2022;36:758‐769.
    pmc: PMC8965264pubmed: 35246994
  14. Hesselkilde EZ, Carstensen H, Flethøj M. Longitudinal study of electrical, functional and structural remodelling in an equine model of atrial fibrillation. BMC Cardiovasc Disord 2019;19:1‐2.
    pmc: PMC6805623pubmed: 31638896
  15. Sharma S, Merghani A, Mont L. Exercise and the heart: the good, the bad, and the ugly. Eur Heart J 2015;23:1445‐1453.
    pubmed: 25839670
  16. Elliott AD, Mahajan R, Linz D. Atrial remodeling and ectopic burden in recreational athletes: implications for risk of atrial fibrillation. Clin Cardiol 2018;41:843‐848.
    pmc: PMC6490079pubmed: 29671875
  17. Manzi V, Castagna C, Padua E. Dose‐response relationship of autonomic nervous system responses to individualized training impulse in marathon runners. Am J Physiol Heart Circ 2009;296:1733‐1740.
    pubmed: 19329770
  18. La Gerche A, Heidbuchel H. Can intensive exercise harm the heart? You can get too much of a good thing. Circulation 2014;130:992‐1002.
    pubmed: 25223770
  19. Mont L, Tamborero D, Elosua R. Physical activity, height, and left atrial size are independent risk factors for lone atrial fibrillation in middle‐aged healthy individuals. Europace 2008;10:15‐20.
    pubmed: 18178694
  20. Myrstad M, Nystad W, Graff‐Iversen S. Effect of years of endurance exercise on risk of atrial fibrillation and atrial flutter. Am J Card 2014;114:1229‐1233.
    pubmed: 25169984
  21. Elliott AD, Linz D, Verdicchio CV, Sanders P. Exercise and atrial fibrillation: prevention or causation?. Heart Lung Circ 2018;27:1078‐1085.
    pubmed: 29891251
  22. Young LE. Cardiac responses to training in 2‐year‐old thoroughbreds: an echocardiographic study. Equine Vet J 1999;31:195‐198.
    pubmed: 10659251
  23. Buhl R, Ersbøll AK, Eriksen L, Koch J. Changes over time in echocardiographic measurements in young Standardbred racehorses undergoing training and racing and association with racing performance. J Am Vet Med Assoc 2005;226:1881‐1887.
    pubmed: 15934256
  24. Mesirca P, Nakao S, Nissen SD. Intrinsic electrical remodeling underlies atrioventricular block in athletes. Circ Res 2021;129:e1‐e20.
    pubmed: 33849278
  25. Nissen SD, Weis R, Krag‐Andersen EK. Electrocardiographic characteristics of trained and untrained standardbred racehorses. J Vet Intern Med 2022;36:1119‐1130.
    pmc: PMC9151491pubmed: 35488721
  26. Deem DA, Fregin GF. Atrial fibrillation in horses: a review of 106 clinical cases, with consideration of prevalence, clinical signs, and prognosis. J Am Vet Med Assoc 1982;180:261‐265.
    pubmed: 7056674
  27. Lo Feudo CM, Stucchi L, Conturba B, Stancari G, Zucca E, Ferrucci F. Medical causes of poor performance and their association with fitness in Standardbred racehorses. J Vet Intern Med 2023;37:1‐14.
    doi: 10.1111/jvim.16734pmc: PMC10365054pubmed: 37148147google scholar: lookup
  28. Stevenson IH, Teichtahl H, Cunnington D, Ciavarella S, Gordon I, Kalman JM. Prevalence of sleep disordered breathing in paroxysmal and persistent atrial fibrillation patients with normal left ventricular function. Heart Lung Circ 2007;16:S200.
    pubmed: 18515807
  29. Linz D, McEvoy RD, Cowie MR. Associations of obstructive sleep apnea with atrial fibrillation and continuous positive airway pressure treatment: a review. JAMA Cardiol 2018;3:532‐540.
    pubmed: 29541763
  30. Buch P, Friberg J, Scharling H, Lange P, Prescott E. Reduced lung function and risk of atrial fibrillation in the Copenhagen City Heart Study. Eur Respir J 2003;21:1012‐1016.
    pubmed: 12797497
  31. Reef VB, Davidson EJ, Slack J, Stefanovski D. Hypercapnia and hyperlactatemia were positively associated with higher‐grade arrhythmias during peak exercise in horses during poor performance evaluation on a high‐speed treadmill. Vet J 2020;266:105572.
    pubmed: 33323171
  32. Marr CM, Franklin S, Garrod G. Exercise‐associated rhythm disturbances in poorly performing thoroughbreds: risk factors and association with racing performance. Equine Vet J 2021;53:656‐669.
    pubmed: 32979227
  33. Hinchcliff KW, Jackson MA, Brown JA. Tracheobronchoscopic assessment of exercise‐induced pulmonary hemorrhage in horses. Am J Vet Res 2005;66:596‐598.
    pubmed: 15900938
  34. Crispe EJ, Secombe CJ, Perera DI, Manderson AA, Turlach BA, Lester GD. Exercise‐induced pulmonary haemorrhage in thoroughbred racehorses: a longitudinal study. Equine Vet J 2019;51:45‐51.
    pubmed: 29675969
  35. Gerber V, Straub R, Marti E. Endoscopic scoring of mucus quantity and quality: observer and horse variance and relationship to inflammation, mucus viscoelasticity and volume. Equine Vet J 2004;36:576‐582.
    pubmed: 15581321
  36. Holcombe SJ, Robinson NE, Derksen FJ. Effect of tracheal mucus and tracheal cytology on racing performance in thoroughbred racehorses. Equine Vet J 2006;38:300‐304.
    pubmed: 16866195
  37. Salz RO, Ahern BJ, Boston R, Begg LM. Association of tracheal mucus or blood and airway neutrophilia with racing performance in thoroughbred horses in an Australian racing yard. Aust Vet J 2016;94:96‐100.
    pubmed: 26952960
  38. Léguillette R, Steinmann M, Bond SL, Stanton B. Tracheobronchoscopic assessment of exercise‐induced pulmonary hemorrhage and airway inflammation in barrel racing horses. J Vet Intern Med 2016;30:1327‐1332.
    pmc: PMC5089608pubmed: 27278854
  39. . Racing Information Select Horse. Hong Kong Jockey Club 2022.
  40. . Racing Australia Horse. Racing Australia 2022.
  41. . Department of Veterinary Regulation Welfare and Biosecurity Policy. Hong Kong Jockey Club 2019.
  42. . Raceday Responsibilities. Racing Victoria 2022.
  43. Holmes JR, Henigan M, Williams RB, Witherington DH. Paroxysmal atrial fibrillation in racehorses. Equine Vet J 1986;18:37‐42.
    pubmed: 3948829
  44. Crispe EJ, Lester GD, Secombe CJ, Perera DI. The association between exercise‐induced pulmonary haemorrhage and race‐day performance in thoroughbred racehorses. Equine Vet J 2017;49:584‐589.
    pubmed: 28118491
  45. Morley PS, Bromberek JL, Saulez MN, Hinchcliff KW, Guthrie AJ. Exercise‐induced pulmonary haemorrhage impairs racing performance in thoroughbred racehorses. Equine Vet J 2015;47:358‐365.
    pubmed: 25290262
  46. Hinchcliff KW, Morley PS, Jackson MA. Risk factors for exercise‐induced pulmonary haemorrhage in thoroughbred racehorses. Equine Vet J 2010;42:228‐234.
    pubmed: 21059011
  47. Birks EK, Shuler KM, Soma LR. EIPH: postrace endoscopic evaluation of Standardbreds and thoroughbreds. Equine Vet J 2002;34:375‐378.
    pubmed: 12405719
  48. Raphel CF, Soma L. Exercise‐induced pulmonary hemorrhage in thoroughbreds after racing and breezing. Am J Vet Res 1982;43:1123‐1127.
    pubmed: 7103190
  49. Hinchcliff KW, Jackson MA, Morley PS. Association between exercise‐induced pulmonary hemorrhage and performance in thoroughbred racehorses. J Am Vet Med Assoc 2005;227:768‐774.
    pubmed: 16178399
  50. West JB, Mathieu‐Costello OD, Jones JH. Stress failure of pulmonary capillaries in racehorses with exercise‐induced pulmonary hemorrhage. J Appl Physiol 1993;75:1097‐1109.
    pubmed: 8226517
  51. Manohar M. Pulmonary artery wedge pressure increases with high‐intensity exercise in horses. Am J Vet Res 1993;54:142‐146.
    pubmed: 8427458
  52. Bayly W. Exercise‐induced pulmonary hemorrhage—an occupational hazard of high‐speed exercise. AAEP Proc 2021;30:31.
  53. White CW, Kerber RE, Weiss HR, Marcus ML. The effects of atrial fibrillation on atrial pressure‐volume and flow relationships. Circ Res 1982;51:205‐215.
    pubmed: 7094230
  54. Koblinger K, Nicol J, McDonald K. Endoscopic assessment of airway inflammation in horses. J Vet Intern Med 2011;25:1118‐1126.
    pubmed: 21985142
  55. Ramzan P, Parkin T, Shepherd M. Lower respiratory tract disease in thoroughbred racehorses: analysis of endoscopic data from a UK training yard. Equine Vet J 2008;40:7‐13.
    pubmed: 18083654
  56. Cardwell JM, Wood JL, Smith KC, Newton JR. Descriptive results from a longitudinal study of airway inflammation in British National Hunt racehorses. Equine Vet J 2011;43:750‐755.
    pubmed: 21496098
  57. Couëtil LL, Cardwell JM, Gerber V, Lavoie JP, Léguillette R, Richard EA. Inflammatory airway disease of horses—revised consensus statement. J Vet Intern Med 2016;30:503‐515.
    pmc: PMC4913592pubmed: 26806374
  58. Christley RM, Hodgson DR, Rose RJ. A case‐control study of respiratory disease in thoroughbred racehorses in Sydney, Australia. Equine Vet J 2001;33:256‐264.
    pubmed: 11352347
  59. Sanchez A, Couetil LL, Ward MP, Clark SP. Effect of airway disease on blood gas exchange in racehorses. J Vet Intern Med 2005;19:87‐92.
    pubmed: 15715053
  60. Saulez MN, Gummow B. Prevalence of pharyngeal, laryngeal and tracheal disorders in thoroughbred racehorses, and effect on performance. Vet Rec 2009;165:431‐435.
    pubmed: 19820257
  61. Ter Woort F, Dubois G, Tansley G. Validation of an equine fitness tracker: ECG quality and arrhythmia detection. Equine Vet J 2023;55:336‐343.
    pmc: PMC10078706pubmed: 35138653
  62. La Gerche A, Wasfy MM, Brosnan MJ. The athlete's heart—challenges and controversies: JACC focus seminar 4/4. J Am Coll Cardiol 2022;80:1346‐1362.
    pubmed: 36075838
  63. Heidbuchel H. The athlete's heart is a proarrhythmic heart, and what that means for clinical decision making. EP Europace 2018;20:1401‐1411.
    pubmed: 29244075
  64. Bennet ED, Parkin TD. Fifteen risk factors associated with sudden death in thoroughbred racehorses in North America (2009‐2021). J Am Vet Med Assoc 2022;1:1‐7.
    pubmed: 36264714
  65. Lyle CH, Blissitt KJ, Kennedy RN. Risk factors for race‐associated sudden death in thoroughbred racehorses in the UK (2000‐2007). Equine Vet J 2012;44:459‐465.
    pubmed: 22128788
  66. Nath L, Stent A, Elliott A, La Gerche A, Franklin S. Risk factors for exercise‐associated sudden cardiac death in thoroughbred racehorses. Animals 2022;12:1297.
    pmc: PMC9137751pubmed: 35625143
  67. Morrice‐West AV, Hitchens PL, Walmsley EA, Stevenson MA, Whitton RC. Training practices, speed and distances undertaken by thoroughbred racehorses in Victoria, Australia. Equine Vet J 2020;52:273‐280.
    pubmed: 31386764
  68. Georgopoulos SP, Parkin TD. Risk factors associated with fatal injuries in thoroughbred racehorses competing in flat racing in the United States and Canada. J Am Vet Med Assoc 2016;249:931‐939.
    pubmed: 27700272
  69. Hitchens PL, Morrice‐West AV, Stevenson MA, Whitton RC. Meta‐analysis of risk factors for racehorse catastrophic musculoskeletal injury in flat racing. Vet J 2019;245:29‐40.
    pubmed: 30819423
  70. Seshadri DR, Thom ML, Harlow ER. Wearable technology and analytics as a complementary toolkit to optimize workload and to reduce injury burden. Front Sports Act Living 2021;2:228.
    pmc: PMC7859639pubmed: 33554111
  71. Vermeulen AD, Evans DL. Measurements of fitness in thoroughbred racehorses using field studies of heart rate and velocity with a global positioning system. Equine Vet J 2006;38:113‐117.
    pubmed: 17402404
  72. Ryan N, Marr CM, McGladdery AJ. Survey of cardiac arrhythmias during submaximal and maximal exercise in thoroughbred racehorses. Equine Vet J 2005;37:265‐268.
    pubmed: 15892238
  73. Visser EK, Van Reenen CG, Van der Werf JT. Heart rate and heart rate variability during a novel object test and a handling test in young horses. Physiol Behav 2002;76:289‐296.
    pubmed: 12044602
  74. Navas de Solis C, Green C, Sides R, Seino K, Bayly W. Arrhythmias in thoroughbreds during and after treadmill and racetrack exercise. Equine Vet J 2014;46:24‐25.

Citations

This article has been cited 2 times.
  1. Kuroda T, Minamijima Y, Kinman CK, Takahashi Y, Ebisuda Y, Inoue K, Ishikawa H, Mita H, Tamura N, Nukada T, Toutain PL, Ohta M. Rational quinidine dosage regimen for atrial fibrillation in Thoroughbred racehorses based on population pharmacokinetics. Front Vet Sci 2024;11:1454342.
    doi: 10.3389/fvets.2024.1454342pubmed: 39439824google scholar: lookup
  2. Ding P, Song Y, Yang Y, Zeng C. NLRP3 inflammasome and pyroptosis in cardiovascular diseases and exercise intervention. Front Pharmacol 2024;15:1368835.
    doi: 10.3389/fphar.2024.1368835pubmed: 38681198google scholar: lookup
Subscribe to our newsletter
Join 99,727 horse owners like you who receive our email updates on horse health and nutrition.