KIT and atrial fibrillation: Most of the studies have utilized AF-MSCs obtained during the second trimester (16–28 weeks) through amniocentesis [148,149,150,151,152] Very few studies have utilized AF isolated during first trimester and during parturition [153,154] AF-MSCs are isolated from AF by centrifuging and then culturing the cells at specific conditions, then the cells are sorted using CD117.