What is the primary function of a defibrillator?

The primary function of a defibrillator is to restore a normal heart rhythm by delivering an electric shock. Defibrillators are crucial medical devices used in emergencies, especially for patients experiencing life-threatening arrhythmias such as ventricular fibrillation or pulseless ventricular tachycardia. When these abnormal heart rhythms occur, the heart's electrical activity becomes chaotic, preventing it from effectively pumping blood.

By delivering a controlled electric shock, a defibrillator can interrupt this disorganized electrical activity and allow the heart's natural pacemaker to reset, leading to the restoration of a normal rhythm. This process significantly increases the chances of survival for patients in cardiac arrest situations.

While other functions listed, like measuring heart activity or assisting with breathing, are vital in patient care, they are not the primary role of a defibrillator. Maintenance of equipment is also essential but does not pertain directly to the life-saving functions of a defibrillator. Hence, the correct answer highlights the defibrillator's critical role in emergency cardiovascular care.