ASSOCIATION OF LOW SODIUM-POTASSIUM RATIO WITH ATRIAL FIBRILLATION IN PATIENTS WITH PRIMARY ALDOSTERONISM

Abstract

Objective: Atrial fibrillation (AF) is the most common cardiac arrhythmia with an increasing incidence and prevalence. Mechanisms of AF in patients with RHTN are not well studied. Obesity, high dietary salt intake and primary aldosteronism (PA) are commonly found. We have previously shown that AF is more common in patients with PA. Epidemiological studies suggest that the urinary sodium-to-potassium ratio may be a superior metric as compared to separate sodium and potassium values for determining the relation to blood pressure and cardiovascular disease risks. In this cross-sectional study we investigated the role of 24 h urinary sodium-to-potassium (24hUNaK) ratio in patients with AF and PA versus AF and non-PA. Design and method: This cross-sectional study of a large cohort of 2,375 black and white resistant hypertensive patients seen at the University of Alabama at Birmingham investigated the association of 24hUNaK ratio in patients with AF and PA vs AF and non-PA. PA was defined as renin activity <1ng/mL/h, aldosterone-renin-ratio >20, and 24 h UAldo >12mcg. Resistant hypertension was defined as blood pressure (BP) > 130/80 mmHg while taking 3 or more different antihypertensive medications, including a diuretic, if tolerated Results: Prevalence of AF in patients with PA vs non-PA was higher(18.5 vs 6.9%, p = 0.009). Patients with AF and PA were younger and more often male while rates of obesity, dyslipidemia, heart failure, obstructive sleep apnoea, diabetes, and coronary artery disease. There was no difference in clinic BP levels, duration of hypertension, and number of antihypertensive medications. Patients with AF and PA had a significant lower serum potassium (3.8+/−0.4 vs 4.2+/−0.5 mEq/dL, p < 0.001), higher 24 h urinary potassium levels (82.8+/−34.2 vs 53.1+/−22.8 mEq), higher 24 h urinary sodium levels (179.6+/−77.5 vs 149.1+/−69.2 mEq, p = 0.007), and lower 24 h UNaK ratio compared to patients with AF and non-PA (2.35+/−1.1 vs 3.05+/−1.3, p = 0.0003). Conclusions: A significant lower 24 h UNaK ratio was associated with AF in PA patients. Benefits for a reduction in sodium and an increase in potassium have been shown in patients with hypertension. Using the UNaK ratio as tool and improvement through diet and medical therapy, i.e. mineralocorticoid receptor antagonism may be key to prevent AF.