Cardiac Pathology and Genomics of Sudden Death in Racehorses From New York and Maryland Racetracks.
Abstract: Postmortem evaluation of racehorses has focused primarily on musculoskeletal injuries; however, horses also die suddenly on the track (sudden death [SD]). Although cardiac conditions are frequently suspected as a cause of death, SD racehorses are often autopsy negative; however, previous studies have been limited due to inconsistent or insufficient cardiac sampling and lack of controls. SD in New York (NY) and Maryland (MD) racehorses was evaluated in an observational case vs control study comparing clinical information, postmortem evaluation including cardiac dissection, and cardiac conduction system histopathology. In the study period, there were 40 cases of SD. In NY, SD occurred in 12% (37/316) of submissions, and 36 (11%) cases of SD were exercise associated (EASD); 3 EASD cases occurred in MD. In NY/MD EASD cases with histologic examination of the heart, 11 of 36 (31%) had significant lesions, including mesenteric artery rupture (1), axial trauma (2), systemic inflammation (2), pulmonary hemorrhage (1), and cardiac disease (5). Mild myocardial fibrosis, mild inflammation, coronary arteriosclerosis, and variation in cardiac nodal connective tissue were present in both SD cases and controls and thus were not considered to be causes of SD. While not excluding a genetic basis for SD, analysis of the genotypes (GGP Equine 70 K Array) of cases and controls did not reveal significant differences in allele frequencies at any locus. Most SD racehorses were autopsy negative; further research using standardized protocols and controls is needed to understand the underlying causes of SD, which is crucial to protecting the viability of racing.
Publication Date: 2019-03-27 PubMed ID: 30917748DOI: 10.1177/0300985819829529Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article discusses the evaluation of sudden death (SD) in racehorses from New York and Maryland, highlighting that while cardiac conditions are often suspected causes of death, many instances have inconclusive autopsy results due to inconsistent cardiac sampling or lack of control groups. The research didn’t find significant differences in gene types between suddenly deceased horses and control groups, indicating that a genetic basis for SD isn’t confirmed.
Research Approach
- The researchers conducted an observational case-control study wherein they compared clinical information, postmortem evaluation (including cardiac dissection), and cardiac conduction system histopathology.
- In the course of the study, there were 40 cases of SD. In New York, SD occurred in 12% of submissions, and 36 cases of SD were exercise associated. Three exercise-associated SD cases occurred in Maryland.
- Horses that had died suddenly were dissected, with special attention paid to the heart and its histological examination.
Findings
- In the cases with a histologic examination of the heart, 31% had significant lesions such as mesenteric artery rupture, axial trauma, systemic inflammation, pulmonary hemorrhage, and cardiac disease.
- Some conditions like mild myocardial fibrosis, mild inflammation, coronary arteriosclerosis, and variation in cardiac nodal connective tissue were found in both the deceased horses and the controls – hence, they were not considered to be causes of SD.
Genetic Analysis
- The researchers analyzed the genetic make-up (genotypes) of the dead horses and the controls, specifically using the GGP Equine 70 K Array – a tool designed for genomic evaluation of horses.
- The comparison did not reveal significant differences in allele frequencies at any genetic loci. This does not support a genetic basis for SD in the horses.
Overall Outcome
- The majority of the SD racehorses had negative autopsy results, leaving the cause of their death undefined.
- The authors suggest that more research is necessary, using standardized protocols and controls, to understand the root causes of SD.
- This understanding is crucial in developing preventative measures and safeguarding the viability and safety of horse racing.
Cite This Article
APA
Molesan A, Wang M, Sun Q, Pierce V, Desideri R, Palmer S, Todhunter R, Kelly K.
(2019).
Cardiac Pathology and Genomics of Sudden Death in Racehorses From New York and Maryland Racetracks.
Vet Pathol, 56(4), 576-585.
https://doi.org/10.1177/0300985819829529 Publication
Researcher Affiliations
- 1 Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- 2 Computational Biology Service Unit, Cornell University, Ithaca, NY, USA.
- 2 Computational Biology Service Unit, Cornell University, Ithaca, NY, USA.
- 3 College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- 1 Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- 4 Departments of Biomedical Sciences and Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- 5 New York State Gaming Commission, Schenectady, NY, USA.
- 6 Deptartment of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
- 1 Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
MeSH Terms
- Animals
- Autopsy / veterinary
- Coronary Artery Disease / pathology
- Coronary Artery Disease / veterinary
- Death, Sudden, Cardiac / pathology
- Death, Sudden, Cardiac / veterinary
- Female
- Genomics
- Hemorrhage / pathology
- Hemorrhage / veterinary
- Horse Diseases / diagnosis
- Horse Diseases / pathology
- Horses
- Lung Diseases / pathology
- Lung Diseases / veterinary
- Male
- Maryland
- Myocardium / pathology
- New York
- Physical Conditioning, Animal
- Retrospective Studies
Citations
This article has been cited 10 times.- Gibson MJ, Legg KA, Gee EK, Rogers CW. The Reporting of Racehorse Fatalities in New Zealand Thoroughbred Flat Racing in the 2011/12-2021/22 Seasons. Animals (Basel) 2023 Feb 9;13(4).
- Nath L, Stent A, Elliott A, La Gerche A, Franklin S. Risk Factors for Exercise-Associated Sudden Cardiac Death in Thoroughbred Racehorses. Animals (Basel) 2022 May 18;12(10).
- Hellings IR, Skjerve E, Karlstam E, Valheim M, Ihler CF, Fintl C. Racing-associated fatalities in Norwegian and Swedish harness racehorses: Incidence rates, risk factors, and principal postmortem findings. J Vet Intern Med 2022 Mar;36(2):778-786.
- 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 Mar;35(2):1111-1120.
- Goto Asakawa M, Mehmood W, Ali M, Oikawa MA. Idiopathic multifocal myocardial atrophy with fibrosis and fatty infiltration involving Purkinje fibres in a 13-year-old Arabian broodmare: Histopathological features. Vet Med Sci 2021 Jan;7(1):3-8.
- Kapusniak A, Lara NM, Hitchens PL, Bailey S, Nath L, Franklin S. Use of Artificial Intelligence to Detect Cardiac Rhythm Disturbances in Athletes: A Scoping Review. J Vet Intern Med 2025 Nov-Dec;39(6):e70257.
- Avison A, Physick-Sheard PW, Pyle WG. Performance horses as a model for exercise-associated cardiac arrhythmias and sudden cardiac death. J Mol Cell Cardiol Plus 2025 Jun;12:100452.
- Gómez-Torres F, Ballesteros-Acuña L, Ruíz-Sauri A. Histological and morphometric changes in cardiac conduction fibers after spontaneous myocardial infarction in horses and dogs. Vet World 2025 Apr;18(4):827-836.
- Nath LC, Saljic A, Buhl R, Elliott A, La Gerche A, Ye C, Schmidt Royal H, Lundgren Virklund K, Agbaedeng TA, Stent A, Franklin S. Histological evaluation of cardiac remodelling in equine athletes. Sci Rep 2024 Jul 19;14(1):16709.
- Kapusniak A, Nath L, Hebart M, Franklin S. Heritability of sudden cardiac death in Thoroughbred racehorses. Equine Vet J 2025 Mar;57(2):325-332.
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