PECAM1 and atrial fibrillation: Our findings revealed that both normal AF-MSCs and ICHD AF-MSCs differentiated into cardiovascular tri-lineages and expressed cTNT, CD31, and SMA; however, the expression of these proteins was significantly down-regulated in ICHD AF-MSCs compared to normal AF-MSCs, suggesting that ICHD AF-MSCs have lower efficiency of differentiating into cardiovascular lineages.