Collins SP, et al. - As early detection of diuretic resistance among patients with acute heart failure (AHF) could facilitate escalation of therapy and prevention of worsening HF (WHF), researchers prospectively studied patients with AHF in emergency department (ED) care to assess the predictive strength of WHF based on early urine electrolyte patterns during the first 1–2 hours of ED care. They defined worsening HF as clinically persistent or WHF requiring escalation of diuretics or administration of intravenous vasoactives after the ED stay. They found that a urine sodium excretion of < 35.4 mmol 1 hour after diuretic administration was highly predictive of WHF development.