GDF5 and atrial fibrillation: Given the close proximity of the atrial appendage to the left ventricle and the fact that removal of the left atrial appendage leads to significant changes in the left ventricle, as well as the relationship between dysfunction of the left ventricle and atrial appendage in heart disorders such as atrial fibrillation, congestive heart failure, and myocardial infarction26,27, it is conceivable that pre-existing dysregulation of an important gene such as GDF5 in the atrial appendage may affect left ventricle function.