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Updated: Jan 14, 2026
A Preclinical Model of Exertional Heat Stroke in Mice
Published on: July 1, 2021
Cardiac Involvement After Exertional Heatstroke: Short-Term Cardiac MRI Follow-Up Study
Jun Zhang1, Xiang Kong1, Li Qi1
1Department of Radiology, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, Jiangsu, China.
Insights
Exertional heatstroke (EHS) can cause heart muscle damage, with MRI showing persistent abnormalities like elevated native T1 and extracellular volume (ECV) at 3 months. Patients with residual cardiac changes should not resume unrestricted training.
Area of Science:
- Cardiology
- Sports Medicine
- Medical Imaging
Background:
- Myocardial involvement is a key feature of exertional heatstroke (EHS).
- The short-term clinical outcomes of cardiac changes in EHS are not well understood.
Purpose of the Study:
- To evaluate serial changes in left ventricular structure and function using cardiac MRI.
- Assess cardiac MRI parameters at baseline and 3-month follow-up in EHS patients.
Main Methods:
- Prospective study involving 41 EHS patients and 27 healthy controls (HCs).
- Cardiac MRI utilized cine, T1, ECV, late gadolinium enhancement (LGE), and T2 sequences at 3.0T.
- Statistical analysis included t-tests, ANOVA, and Kendall's τ-b, with p < 0.05 considered significant.
Main Results:
- EHS patients showed partial improvements in native T1, ECV, T2, and global longitudinal strain at 3 months.
- However, native T1 and ECV remained significantly higher in EHS patients compared to HCs at follow-up.
- Elevated native T1, ECV, and LGE presence at 3 months correlated with reported cardiac symptoms.
Conclusions:
- Cardiac MRI reveals persistently elevated native T1 and ECV at 3 months post-EHS, despite some recovery.
- Residual cardiac abnormalities in EHS patients are linked to ongoing symptoms.
- Individuals with persistent cardiac changes should not be cleared for unrestricted physical activity.
Background:
Myocardial involvement is a major manifestation of exertional heatstroke (EHS), yet its short-term clinical outcome remains unclear.
Purpose:
To assess serial cardiac left ventricular structural and functional changes using baseline and 3-month cardiac MRI.
Study Type:
Prospective.
Population:
A total of 41 participants (median age, 21 years; IQR, 20-23 years) hospitalized for EHS and 27 age-, sex-, and training-matched healthy controls (HCs).
Field Strength/Sequence:
Fast imaging employing steady-state acquisition (cine imaging), saturation methods using adaptive recovery times (native T1, extracellular volume [ECV]), phase-sensitive inversion-recovery gradient recalled echo (late gadolinium enhancement [LGE]), and multi-echo fast spin echo (T2) sequences at 3.0 T.
Assessment:
Longitudinal comparisons were performed within the EHS group (baseline vs. 3-month follow-up), and cross-sectional comparisons were performed between patients and HCs. Cardiac symptoms (chest pain, dyspnea, palpitations, and syncope) at follow-up were recorded using standardized questionnaires.
Statistical Tests:
Paired sample t-test, independent sample t-test, analysis of variance, Kendall's τ-b. A p value < 0.05 was considered significant.
Results:
Significant improvements were observed in native T1 (1492 ± 52 ms vs. 1521 ± 57 ms), ECV (23.4% ± 1.7% vs. 24.3% ± 1.8%), T2 (45.9 ± 2.2 ms vs. 47.3 ± 2.3 ms), and 2D global longitudinal strain (-16.7% ± 1.6% vs. -15.8% ± 1.1%) at 3 months follow-up compared to baseline parameters in the EHS cohort. However, native T1 (1492 ± 52 ms vs. 1456 ± 26 ms) and ECV (23.4% ± 1.7% vs. 20.6% ± 1.6%) at follow-up were significantly higher in EHS than in HCs. At 3-month follow-up, native T1, ECV, and LGE presence were associated with cardiac symptoms (Kendall's τ-b = -0.430, -0.447, and -0.398, respectively).
Data Conclusion:
This study demonstrated persistently elevated native T1 and ECV at 3 months following EHS, despite partial improvement. Those with residual abnormalities should not be cleared for unrestricted training.
Evidence Level:
2.
Technical Efficacy:
Stage 2.
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