part of membrane depolarization membrane depolarization during cardiac muscle cell action potential bundle of His cell action potential membrane depolarization during bundle of His cell action potential GO:0086048 biological_process The process in which bundle of His cardiac muscle cell membrane potential changes in the depolarizing direction from the negative resting potential towards the positive membrane potential that will be the peak of the action potential. dph 2011-11-16T10:56:26Z membrane depolarization during bundle of His cardiac muscle cell action potential