part of atrial cardiac muscle cell differentiation cardiac muscle cell fate commitment atrial cardiac muscle cell fate commitment atrial cardiomyocyte cell fate commitment 2009-09-29T11:46:10Z biological_process atrial heart muscle cell fate commitment GO:0060924 dph The commitment of cells to atrial cardiac muscle cell fates and their capacity to differentiate into cardiac muscle cells of the atrium. Cardiac muscle cells are striated muscle cells that are responsible for heart contraction.