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Home / Equine Research Bank / Animals (Basel) / Seasonal Trends in Cardiac Troponin I Concentration and Crea...
Animals : an open access journal from MDPI2025; 15(21); 3198; doi: 10.3390/ani15213198

Seasonal Trends in Cardiac Troponin I Concentration and Creatine Kinase and Aspartate Aminotransferase Enzyme Activity in Relation to Myocardial Velocity Rates in Eventing Horses.

Abstract: This study examines seasonal changes in muscle and heart parameters in eventing horses over the course of a competition season. Blood levels of the enzymes creatine kinase (CK) and aspartate aminotransferase (AST) as well as the heart muscle-specific concentration of cardiac troponin I (cTnI) were measured before (pre), 30 min (p30) and 24 h (p24) after competitions. Creatine kinase (CK: median pre-competition = 175 U/L, 30 min post = 221 U/L, 24 h post = 140 U/L), aspartate aminotransferase (AST: pre = 319 U/L, p30 = 335 U/L, p24 = 333 U/L), and cardiac troponin I concentration (cTnI: pre = 0.006 ng/mL, p30 = 0.011 ng/mL, p24 = 0.007 ng/mL) exhibited partial normalization by 24 h post-exercise but at the same time demonstrated significant seasonal variation ( < 0.001). Echocardiographic assessments revealed sustained high-level myocardial velocities, with occasional modest seasonal declines. A significant correlation was identified between cTnI levels and early diastolic myocardial velocity (Em) (Spearman's Rho: pre-exercise 0.323, Rho p30: 0.357), whereas a negative correlation was manifest at 24 h (Spearman's Rho = -0.300). These findings suggest a heightened sensitivity of diastolic myocardial velocity to myocardial injury. Given that diastolic dysfunction frequently constitutes an early manifestation of myocardial compromise, our results underscore the utility of biomarkers alongside myocardial velocity measures as valuable tools for the early detection of subclinical fatigue in high-performance sport horses.
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Publication Date: 2025-11-03 PubMed ID: 41227528PubMed Central: PMC12609205DOI: 10.3390/ani15213198Google Scholar: Lookup
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  • 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.

Overview

  • This study investigated seasonal changes in certain blood enzymes and heart muscle parameters in eventing horses throughout a competition season.
  • Researchers measured levels of specific enzymes (CK, AST) and a heart muscle protein marker (cTnI) pre- and post-competition to assess muscle and heart stress, correlating these with heart muscle velocity data obtained by echocardiography.

Introduction and Background

  • Eventing horses undergo intense physical activity, potentially affecting their muscle and heart function over time.
  • Cardiac troponin I (cTnI) is a biomarker specific to heart muscle injury and stress, while creatine kinase (CK) and aspartate aminotransferase (AST) are enzymes related to muscle metabolism and damage.
  • The early diastolic myocardial velocity (Em) is a measure of the heart muscle’s relaxation function, obtainable through echocardiography, and can reflect early cardiac dysfunction.

Methods

  • The study tracked blood levels of CK, AST, and cTnI at three time points relative to competitions: pre-exercise, 30 minutes post-exercise (p30), and 24 hours post-exercise (p24).
  • Echocardiographic measurements were taken to assess myocardial velocity rates, particularly focusing on early diastolic myocardial velocity (Em).
  • Seasonal variations were analyzed statistically to determine if enzyme levels or heart function indicators changed across the competition season.
  • Correlations between enzyme or biomarker concentrations and myocardial velocities were calculated to explore relationships between biomarkers and cardiac function.

Key Findings: Enzyme and Biomarker Levels

  • Creatine kinase (CK) levels increased 30 minutes post-exercise compared to pre-exercise (175 U/L pre vs. 221 U/L at 30 min), then mostly normalized by 24 hours (140 U/L).
  • Aspartate aminotransferase (AST) levels were relatively stable but slightly elevated after exercises (319 U/L pre vs. 335 U/L at 30 min and 333 U/L at 24 h).
  • Cardiac troponin I (cTnI) increased shortly after exercise (0.006 ng/mL pre to 0.011 ng/mL at 30 min) and diminished closer to baseline by 24 hours (0.007 ng/mL).
  • All three markers exhibited significant seasonal variation, indicating that their baseline and exercise response levels change across the competition season.

Key Findings: Cardiac Function (Myocardial Velocity) and Correlations

  • Myocardial velocity rates remained generally high throughout the season, reflecting good heart muscle function in high-performance horses.
  • Some modest seasonal declines in myocardial velocity were observed, which may indicate subtle cardiac fatigue or adaptation over time.
  • A positive correlation existed between cTnI and early diastolic myocardial velocity (Em) before exercise and at 30 minutes post-exercise (Spearman’s Rho ~ 0.32 to 0.36), suggesting that higher cardiac stress markers are associated with increased myocardial relaxation velocity shortly after exercise.
  • At 24 hours post-exercise, this relationship became negative (Spearman’s Rho = -0.30), possibly indicating transient changes in diastolic function following exercise-induced stress or injury.

Interpretation and Significance

  • The increase and subsequent partial normalization of CK, AST, and cTnI post-exercise indicate that these markers respond to exercise-induced muscle and cardiac stress but tend to stabilize within a day.
  • The seasonal variation in these biomarkers suggests cumulative effects or adaptations over a competition season, which could influence the interpretation of individual test results depending on timing.
  • The strong link between cTnI and diastolic myocardial velocity emphasizes the close relationship between biochemical evidence of cardiac injury and functional measures of the heart’s relaxation phase.
  • Because diastolic dysfunction can be an early indicator of myocardial compromise, monitoring both biomarkers like cTnI and echocardiographic myocardial velocity can facilitate early detection of subclinical cardiac fatigue in eventing horses.
  • These measures could be instrumental for veterinarians and trainers in managing training loads, preventing cardiac injury, and optimizing performance in high-level equine athletes.

Conclusion

  • The study highlights the dynamic nature of muscle and heart biomarkers in eventing horses throughout a competition season.
  • Combining biochemical blood markers and echocardiographic measures offers a promising approach for early detection of cardiac stress and fatigue.
  • Regular monitoring of these parameters can improve understanding of equine cardiac health and aid in preventing overtraining or cardiac injury in sport horses.

Cite This Article

APA
Rump-Dierig I, Giers J, Frenzel C, Stöckle S, Gehlen H. (2025). Seasonal Trends in Cardiac Troponin I Concentration and Creatine Kinase and Aspartate Aminotransferase Enzyme Activity in Relation to Myocardial Velocity Rates in Eventing Horses. Animals (Basel), 15(21), 3198. https://doi.org/10.3390/ani15213198

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 15
Issue: 21
PII: 3198

Researcher Affiliations

Rump-Dierig, Insa
  • German Olympic Committee for Equestrian Sports, 48231 Warendorf, Germany.
Giers, Johanna
  • Equine Clinic: Surgery and Radiology, Freie Universität Berlin, 14163 Berlin, Germany.
Frenzel, Charlotte
  • Equine Clinic: Surgery and Radiology, Freie Universität Berlin, 14163 Berlin, Germany.
Stöckle, Sabita
  • Equine Clinic: Surgery and Radiology, Freie Universität Berlin, 14163 Berlin, Germany.
Gehlen, Heidrun
  • Equine Clinic: Surgery and Radiology, Freie Universität Berlin, 14163 Berlin, Germany.

Grant Funding

  • ZMVI4-070101_16-17 / Bundesinstitut für Sportwissenschaften (BISp)

Conflict of Interest Statement

The authors declare no conflicts of interest.

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