The co-existence of atrial fibrillation (AF) and acute heart failure (AHF) is frequently reported and can exacerbate either or both of them. Their combination leads to increased morbidity and mortality. Although there has been a lack of studies on the prevalence and significance, as well as the treatment, of AF in patients with AHF, a position statement from the Acute Cardiovascular Care Association and European Heart Rhythm Association has recently reviewed the latest evidence on AF in the setting of AHF. The purpose of this paper is to briefly overview the crucial aspects of this consensus document.