β-Myosin is more energetically efficient than α-Myosin, so the switch from α to β-Myosin expression (predominant) could be an adaptation toward energetic relief for LA myocytes, as AF results in metabolic stress (45, 46), so increasing the ATP-efficient, stronger myosin isoform may assist in reducing metabolic load. Here, MYH14 is linked to atrial fibrillation.