Cardiac arrest

Sudden cardiac death
Cardiac crisis
Acute coronary syndrome

Nature

A cardiac arrest is when an bio-electrical issue or malfunction causes a lethal rhythm disturbance that stops the heart and causes sudden death. A heart attack is related to a blockage in the blood flow in or around the heart, perhaps from a clot or vascular plaque, usually causing part of the heart muscle to die. The latter can also cause the former.