Hypomagnesemia and Its association with arrhythmia risk in patients with heart failure with reduced ejection fraction: A cross sectional analytical study.

Abstract

Objective: To evaluate the association between serum magnesium concentration and clinically significant arrhythmias in patients with heart failure with reduced ejection fraction. Study Design: Analytical Cross Sectional. Setting: Department of Biochemistry, Shahida Islam Medical and Dental College, Lodhran. Period: October 2025 to February 2026. Methods: Total of 185 adults with confirmed systolic dysfunction (left ventricular ejection fraction ≤40%). Hypomagnesemia was defined as fasting serum magnesium <0.70 mmol/L. Arrhythmia burden was ascertained using standardized electrocardiography and ambulatory rhythm monitoring. Multivariable logistic regression quantified independent associations after rigorous adjustment for demographic, renal, electrolyte, and guideline-directed pharmacological confounders. Statistical significance was considered at p value <0.05. Results: Hypomagnesemia affected 15.7% of participants, while 36.8% exhibited clinically significant arrhythmias, predominantly atrial fibrillation and frequent ventricular ectopy. Unadjusted analysis revealed markedly elevated arrhythmia prevalence (odds ratio: 2.89; p=0.009). Following comprehensive covariate adjustment, low serum magnesium remained independently associated with arrhythmia occurrence (adjusted odds ratio: 2.14; 95% confidence interval: 1.03–4.45; p=0.041). Concomitant reductions in estimated glomerular filtration rate and serum potassium emerged as additional independent predictors. Model diagnostics demonstrated acceptable discriminatory capacity and calibration. Subgroup evaluations confirmed consistent effect modification across renal and diuretic exposure categories. Conclusion: Hypomagnesemia independently predicts a substantially higher arrhythmia burden in systolic heart failure. Systematic magnesium surveillance and targeted repletion constitute pragmatic, cost-effective strategies for arrhythmia risk mitigation.