FGF23 and atrial fibrillation: Elevated FGF23 levels are associated with all-cause and CV mortality in the general population (71, 72) as well as in CKD patients (73), LV dysfunction and atrial fibrillation (AF) in patients without CV co-morbidities (74, 75), and the development of cardiac hypertrophy (76) and fibrosis (77).