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Animals : an open access journal from MDPI2022; 12(10); 1297; doi: 10.3390/ani12101297

Risk Factors for Exercise-Associated Sudden Cardiac Death in Thoroughbred Racehorses.

Abstract: Cardiac arrhythmias resulting in sudden cardiac death (SCD) are an important cause of racehorse fatalities. The objective of this study was to determine risk factors for SCD in Thoroughbreds by evaluating a sample with a policy of mandatory post-mortem following racing or training fatalities. Risk factors were compared between case horses with SCD (n = 57) and control horses with other fatal injury (OFI, n = 188) by univariable and multivariable logistic regression. Survival in years for horses with SCD was compared to OFI using the Kaplan−Meier method with log rank test. The following variables were most important in the multiple logistic model: Horses with SCD were more likely to die during training than during racing, SCD (42/57, 74%) vs. OFI (82/188, 44%; odds ratio [OR], 95% confidence interval [CI], 2.5, 1.2−5.4; p = 0.01), had fewer lifetime starts, median (interquartile range [IQR]), SCD (3.0 [0.0−9.0]) vs. OFI (9.0 [0.0−22.8]; OR, 95% CI, 0.96, 0.9−1.0; p = 0.02 and were less likely to be entire (uncastrated) males, SCD 9/57 (16%) vs. OFI (46/188, 25%; OR, 95% CI, 0.47, 0.1−0.9; p = 0.03). Survival in years (median (IQR)) for horses with SCD was 3.6 (3.1−4.4), which was shorter than OFI (4.5 [3.1−6.0], hazard ratio, 95%CI, 1.6,1.2−2.3; p < 0.001). SCD occurs more commonly in training than racing, which suggests exercise intensity is less important in precipitating this fatality. In this study, SCD occurred early in the careers of affected horses.
Publication Date: 2022-05-18 PubMed ID: 35625143PubMed Central: PMC9137751DOI: 10.3390/ani12101297Google Scholar: Lookup
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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.

This research aims to identify risk factors for sudden cardiac death (SCD) in Thoroughbred racehorses. The study found that SCD is more likely to occur during training than racing, in horses with fewer lifetime starts and that it is less common in uncastrated males.

Risk Factors for SCD in Thoroughbreds

The study began with the objective of determining the risk factors that contribute to sudden cardiac death in Thoroughbred racehorses. Sudden cardiac death is an important cause of fatalities in racehorses, triggered by cardiac arrhythmias. For this study, a sample of horses with a mandatory post-mortem policy upon death during racing or training was evaluated. The risk factors between horses that suffered from SCD (n=57) and those with other fatal injuries (OFI, n=188) were compared.

  • The factors were compared using univariable and multivariable logistic regression and survival years were calculated with the Kaplan-Meier method with a log-rank test.
  • The study discovered that horses with SCD were more likely to die during training (74% of the time) than during actual races when compared to horses with OFI (44% of the time).

Other Significant Findings

  • Research also revealed that Thoroughbreds with SCD had fewer lifetime starts. The median number of starts was lower for SCD (3) compared to the OFI (9).
  • The study also found SCD to be less likely in uncastrated (entire) males.
  • The survival in years after SCD was shorter than OFI. The median survival rate for horses with SCD was 3.6 years, lower than the 4.5 years survival of horses with OFI.

Key Takeaways

This study definitively showed that SCD occurs more commonly in training than racing, contradicting the often-held belief that exercise intensity is the primary trigger of SCD. This suggests other factors potentially within the control of trainers could be contributing to the onset of SCD. The researchers observed that SCD typically occurs early in the careers of affected Thoroughbreds indicating that it is essential to monitor horses’ cardiac health right from the start of their careers.

Cite This Article

APA
Nath L, Stent A, Elliott A, La Gerche A, Franklin S. (2022). Risk Factors for Exercise-Associated Sudden Cardiac Death in Thoroughbred Racehorses. Animals (Basel), 12(10), 1297. https://doi.org/10.3390/ani12101297

Publication

ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 12
Issue: 10
PII: 1297

Researcher Affiliations

Nath, Laura
  • School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy 5371, Australia.
Stent, Andrew
  • Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee 3030, Australia.
Elliott, Adrian
  • Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide 5005, Australia.
La Gerche, Andre
  • Baker Heart and Diabetes Institute, Melbourne 3004, Australia.
Franklin, Samantha
  • School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy 5371, Australia.

Grant Funding

  • no number / Racing Victoria

Conflict of Interest Statement

The authors declare no conflict of interest.

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