Yang Long et al. [19] proposed that activatingtransforming growth factor-β1 (TGF-β1)/c-Jun N-terminal kinase (JNK)–mitogen-activated protein kinase (MAPK) and extracellular regulated protein kinases (ERK)–MAPK signaling pathways might be implicated in developing atrial fibrillation secondary to valvular heart disease. Here, MAPK8 is linked to heart valve disorder.