Correlation of Lactate Dehydrogenase Levels with Arrhythmia in Classic Severe Heatstroke

Introduction: The incidence and risk factors for arrhythmia in patients with classic severe heatstroke remain poorly understood. This study aimed to investigate the relationship between lactate dehydrogenase (LDH) levels and arrhythmia in these patients. Methods: A retrospective multicenter cohort study was conducted across six hospitals involving patients with classic severe heatstroke. LDH levels were transformed using the natural logarithm, and modified Poisson regression was applied to assess the association between Ln(LDH) and arrhythmia. Receiver operating characteristic (ROC) curve analysis evaluated the predictive performance of LDH alone and in combination with the Sequential Organ Failure Assessment (SOFA) score for arrhythmia incidence. Mediation analysis was used to determine if LDH mediated the relationship between temperature and arrhythmia. Results: Among 261 eligible patients, 80 (30.7%) developed arrhythmia during hospitalization. After adjusting for confounders, modified Poisson regression revealed that higher Ln(LDH) was significantly associated with arrhythmia (adjusted relative risk [aRR] = 1.672, 95% CI = 1.162–2.407). ROC analysis demonstrated favorable predictive performance (AUC = 0.721; 95% CI: 0.657–0.785). The combination of LDH and the SOFA score significantly enhanced predictive accuracy (AUC = 0.789; 95% CI: 0.734–0.845). Mediation analysis showed that LDH partially mediated the relationship between temperature and arrhythmia, explaining 30.5% (95% CI: 15.1%–62.0%) of the association. Conclusion: Elevated LDH is significantly linked to an increased risk of arrhythmia in classic severe heatstroke and demonstrates strong predictive value.