Atrial cardiomyocyte calcium signalling

► Atrial cardiac myocytes make an important contribution to blood pumping. ► Dysregulation of atrial contraction can be debilitating or even fatal. ► Atrial myocytes have a different ultrastructure from ventricular myocytes. ► Calcium regulates heart contraction, and it has a unique pattern in atrial myocytes. ► Atrial myocytes change the pattern of calcium signalling to alter contraction strength.