Second, although exposure of primary cardiomyocytes to FGF23 was reported to result in elevated intracellular calcium and increased ventricular muscle strip contractility in the experimental model [30], whether FGF23 truly represents a useful biomarker, or is a simple bystander, for cardiac dysfunction and hypertrophy should be analyzed in the longitudinal studies. This evidence concerns the gene FGF23 and hypertrophy.