Asystole is defined as?

• A. No electrical activity, not shockable
• B. Chaotic rhythm with a pulse
• C. Rapid rhythm with a pulse
• D. Electrical rhythm with a pulse

Answer: (A)

Asystole means there is no electrical activity in the heart, shown on the ECG as a flat line with no organized rhythm and no detectable pulse. Because there’s no electrical signal to trigger a heartbeat, defibrillation won’t work—it's not a shockable rhythm. The correct approach is immediate high-quality CPR and vasopressor support while you look for reversible causes. This is different from pulseless electrical activity, where some electrical activity is present but the heart’s pumping action is absent, and from rhythms like ventricular fibrillation or pulseless VT, which are chaotic or rapid but are treatable with defibrillation.