<qa>  What is the name of the type of lesions that are classified as simple?Patients with complex congenital heart disease have reduced muscle function compared to healthy controls as well as patients with lesions classified as simple. Furthermore, men with congenital heart disease are more commonly underweight and less commonly overweight obese compared to the general population. In addition, men with complex lesions are shorter in comparison to controls. This indicates an altered body composition i.e. muscle mass, fat mass and bone density in this population. Moreover, impaired muscle metabolism has been reported in patients palliated with Fontan procedure. 