Cardiac Involvement After Exertional Heatstroke: Short-Term Cardiac MRI Follow-Up Study.

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.