The association between serum calcium and chronic heart failure: A cross-sectional observational study

Background: Chronic heart failure (CHF) is characterized by sustained activation of neurohormonal and cytokine systems leading to a series of end-organ changes within the myocardium referred to as left ventricular remodeling. Renin-Angiotensin system activation leading to secondary hyperaldosteronism is accompanied by ionized hypocalcemia with secondary hyperparathyroidism which causes dyshomeostasis of extra and intracellular calcium leading to cardiomyocyte necrosis. Objectives: To study the levels of serum calcium in patients of heart failure and its association with severity and duration of chronic heart failure. Methods: The study was conducted on 50 patients with CHF after taking informed consent. All patients met inclusion and exclusion criteria and underwent blood sampling, urine examination and other relevant investigations. Serum calcium levels were correlated with the severity and duration of CHF statistically. Results: Among the patients studied, 96% with ejection fraction (EF)≤ 35%, 87.5% with EF between 35-40% and 44.4% with EF ≥ 40% had low serum calcium values ≤9 mg/dl (p-value <0.001). All patients with duration of heart failure ≥ 2 years and 70.4% patients with duration of heart failure 1-2 years had low serum calcium levels ≤ 9 mg/dl (p value =0.001). Conclusion: There is a significant positive correlation of serum calcium levels with severity of heart failure as measured by EF and significant negative correlation with duration of CHF and NYHA functional grades. The degree of hypocalcemia correlates with severity of cardiomyocyte injury and extent of the neurohormonal response, and accordingly the corresponding risk of adverse cardiovascular events.