What device is used to deliver an electric shock to restart a stopped heart?

A defibrillator is the device designed specifically to deliver an electric shock to the heart in order to restore a normal rhythm in cases of life-threatening cardiac arrhythmias or when the heart has stopped beating altogether (cardiac arrest). The electric shock delivered by the defibrillator helps to reset the heart's electrical activity, allowing it to regain a normal rhythm and function properly again. This lifesaving device is often used in emergency situations, such as during cardiopulmonary resuscitation (CPR) efforts.

In contrast, a pacemaker is a device that helps regulate the heartbeat by sending electrical impulses to the heart to maintain a steady rhythm, typically for patients with slow heart rates, but it is not used for the immediate restart of a stopped heart. A stethoscope is a tool for listening to internal body sounds, particularly heartbeats and breath sounds, while a sphygmomanometer is used for measuring blood pressure, neither of which delivers electrical shocks or restores heart rhythm.