Methods to assess heart failure in patients with atrial fibrillation using GDF-15 peptides

A method for diagnosing heart failure accompanied by a left ventricular ejection fraction (LVEF) of less than 60% in a subject showing atrial fibrillation, and said method comprising (a) determining the amount of GDF-15 in a sample of said subject; and (b) compare the amount of GDF-15 determined in step a) with a reference amount of GDF-15 whereby cardiac failure will be diagnosed accompanied by a left ventricular ejection fraction (LVEF) less than 60 %.