FGFR4 and cardiac hypertrophy: Several previous studies have suggested that FGF23 may promote cardiac hypertrophy via FGF receptor 4 (FGFR4)-mediated activation of the calcineurin-NFAT signaling pathway [28,29], although to what extent circulating FGF23 reflects myocardial FGF23 in the setting of heart failure remains under discussion [30].