Serum Potassium Levels and Mortality in Acute Myocardial Infarction

Background: Serum potassium is central to myocardial electrophysiology, and both hypokalemia and hyperkalemia have been linked to adverse cardiac events. Data on the relationship between serum potassium status and in-hospital mortality in patients with acute myocardial infarction (AMI) in the Indian population remain limited. Methods: A hospital-based cross-sectional observational study was conducted over 18 months in the Department of General Medicine and Cardiology of a tertiary care teaching hospital. One hundred patients admitted with AMI were enrolled by random sampling and stratified into hypokalemic (n = 9), normokalemic (n = 66), and hyperkalemic (n = 25) groups based on serial serum potassium estimations (flame photometry) performed on Day 0, 1, 3, and 5 of admission. Baseline characteristics, ECG pattern, duration of hospital stay, and in-hospital mortality were compared across groups using one-way ANOVA and the chi-square test, with p < 0.05 considered significant. Results: Overall in-hospital mortality was 28% (28/100). Mortality was 77.8% in the hypokalemic group and 76.0% in the hyperkalemic group, compared with 3.0% in the normokalemic group (χ² = 60.04, p < 0.001). Duration of hospital stay was longest in the normokalemic group (5.65 ± 0.83 days) compared with the hypokalemic (3.56 ± 1.51 days) and hyperkalemic (3.68 ± 1.77 days) groups (p < 0.001). Age, sex, prevalence of diabetes mellitus and hypertension, and ECG pattern did not differ significantly between groups. Conclusion: In-hospital mortality in AMI followed a U-shaped relationship with serum potassium status, with both hypokalemia and hyperkalemia associated with substantially higher mortality than normokalemia. Serum potassium may serve as a simple, widely available prognostic marker in AMI, warranting closer monitoring and correction of dyskalemia in this population.