Profile of acute ST-elevation myocardial infarction patients with hyponatremia

Context: In acute ST-elevation myocardial infarction (STEMI), hyponatremia occurs due to neurohormonal activation. Magnitude of this neurohormonal change is related to the severity of myocardial damage. Aims: This study aimed to document the profile of STEMI with hyponatremia and to evaluate the correlation of hyponatremia with Killip class, creatine kinase-muscle brain (CK-MB) level, and degree of ST-elevation. Settings and Design: A longitudinal study was conducted in a tertiary care teaching hospital, Imphal. Patients and Methods: The study included 100 patients with STEMI. Killip class was ascertained on admission. Serum sodium level was estimated on admission, after 24 h, 48 h, and 72 h. CK-MB level was estimated, and the degree of ST-elevation was measured. Statistical Analysis: Statistical Package for the Social Sciences (SPSS 16.0 version) and Student's t-test, Chi-square test, and Fisher's exact test were used for statistical analysis. P < 0.05 was considered statistically significant. Results: Hyponatremia was observed in 44% of the patients. There was no significant relation of hyponatremia with comorbidities such as hypertension, diabetes mellitus, and dyslipidemia. Hyponatremia was associated with Killip III and IV (P = 0.00), higher CK-MB level (P = 0.010), and higher degree of ST-elevation (P = 0.002). Out of six in-hospital deaths, four had hyponatremia. Conclusion: Since hyponatremia was found to be associated with higher Killip class, elevated CK-MB level, and greater degree of ST-segment elevation, it can be speculated that hyponatremia in STEMI patients can be a predictor of poor outcome. Therefore, serum sodium levels can serve as a simple marker to identify patients at high risk.