Artificial pacemakers treat irregular heart rates and rhythms. Several conditions may be treated by an artificial pacemaker, such as bradyarrhythmias (slow heart rhythms), syncope (fainting spells), congestive heart failure (the heart pumps insufficiently which results to failure in maintaining blood flow), and hypertrophic cardiomyopathy (the heart becomes thick without a cause which results to failure in pumping blood effectively).
I believe it would be A. because that is the muscle that regulates the heart pumping. This would happen because the pacemaker is taking over and it now has no purpose.
