Asystole: Medical Term for Cardiac Flatline in ER

Asystole is the medical term for the complete absence of electrical activity in the heart. It is the most severe arrhythmia and generally considered irreversible. When asystole occurs, the heart stops beating and blood circulation ceases, leading to permanent brain damage, organ failure, and death if not treated immediately. In the TV show ER, doctors call out "asystole" to indicate the patient's heart has stopped, prompting CPR or other resuscitative measures.