Add Yahoo as a preferred source to see more of our stories on Google. Electrocardiograms, or ECGs, record the electrical activity of your heart. Randy Faris/The Image Bank via Getty Images Your ...

Understand how defibrillators work to restart the human heart. Watch as earthquake hits Japan, triggers tsunami warning Prince William reportedly livid over Meghan Markle's Althorp photos Man drops ...

Defibrillators are devices that detect dangerously fast heart rates and deliver shocks like those used during cardiopulmonary resuscitation, also known as CPR, to restart the heart. Understanding how ...