ACE and congestive heart failure: It has been proven that low serum sodium carries worse prognosis in HF and STEMI subjects. We analyzed 4670 patients signed up in the IN-CHF registry. Mild-to-moderate and severe hyponatremia (groups two and three) solely predicted first-year death. The connection between sodium concentration and demise was not linear and a drop of 1 mEq/l of sodium exacerbated death rate only for merits of sodium 142.9 mEq/l or less. This relationship was not modified by beta-blocker and ACE inhibitor therapies.