According to a study published in the European Heart Journal that evaluated the link between different levels of serum potassium and mortality among patients with chronic heart failure, levels within the lower and upper limits of the normal serum potassium range (3.5–4.1 mmol/L and 4.8–5 mmol/L, respectively) were associated with a remarkably increased short-term risk of death. In addition, levels below 3.5 mmol/L and above 6 mmol/L were also associated with increased mortality. In this study that included 19,549 patients with a chronic heart failure, the mortality in the eight strata was 14.4, 8.0, 6.3, 5.0, 5.8, 7.9, 10.3, and 21.1% respectively after 90 days. In multivariable adjusted analysis, patients with potassium levels of 2.8–3.4 mmol/L, 3.5–3.8 mmol/L, 3.9–4.1 mmol/L, 4.8–5.0 mmol/L, 5.1–5.5 mmol/L, and 5.6–7.4 mmol/L had an increased risk of all-cause mortality.