The metabolism of hydrogen which involved hydrogenase was the main reason for the MIC of AZ91 alloy.The SRB accelerated the cathodic reaction through the cathodic depolarization.
Normally, the resting state of sodium channels is stabilized by calcium ions, which prevents them from spontaneously opening and potentially causing depolarization.
This happens because an abnormal contraction signal, called a depolarization, originates from somewhere in the ventricles rather than coming from the pacemaker cells.