An alternative hypothesis may be the coexistence of atrial myopathy, which may determine LA dysfunction and the development of AF due to a fragmentation of atrial conduction; this hypothesis is indirectly supported by observations of individuals with specific Arg633His MYH7 mutations demonstrating less cardiac hypertrophy as compared to other MYH7 mutations but a higher risk of developing AF [57]. The gene discussed is MYH7; the disease is atrial fibrillation.