PIEZO1 and atrial fibrillation: However, in contrast to the tachycardia observed following the overexpression of Piezo1 in cardiomyocytes, no observed difference in cardiac arrythmias was detected in mice harbouring gain-of-function Piezo1 mutations [8], although it should be noted that mice in general are unreliable models of cardiac arrythmias, and in particular atrial fibrillation [9,10].