Hyponatremia is associated with occurrence of atrial fibrillation in outpatients with heart failure and reduced ejection fraction

Abstract

Objectives: Hyponatremia and atrial fibrillation (AF) have been established as strong predictors for worse clinical outcomes in patients with heart failure (HF). However, little is known about hyponatremia in relation to the occurrence of AF. This study aims to investigate the possible relationship between hyponatremia and AF in patients with chronic HF and reduced ejection fraction (HFrEF). Methods: Turkish research team-HF (TREAT-HF) is a network that has been undertaking multicenter, observational cohort studies on HF. A total of 880 patients who had plasma sodium measurement in TREAT-HF data set were included in this study. Hyponatremia was defined as a plasma sodium level of ≤135 mmol/L. The patients were classified into hyponatremia (n=213) or normonatremia (n=667) based on the sodium level. Results: The rate of AF was found to be 33.3% in patients with hyponatremia and 18.8% in patients with normonatremia (p<0.001). Univariate analysis demonstrated an association between hyponatremia and AF. Furthermore, in multivariate logistic regression model, hyponatremia was also found to be significantly and independently associated with the occurrence of AF (odds ratio [OR]=2.457, 95% confidence interval [CI]=1.586-3.806, p<0.001) in addition to other well-known risk factors for AF. Conclusion: The results of this study showed that AF was more prevalent in outpatients with HFrEF and hyponatremia than in those with HFrEF and normonatremia. These results also suggest that hyponatremia is independently associated with the occurrence of AF. Keywords: Heart failure, atrial fibrillation, hyponatremia