Is asystole shockable?

No. Asystole and PEA are non-shockable arrest rhythms. The response is high-quality CPR, epinephrine per ACLS, and aggressively treating reversible causes — defibrillation is not indicated.

How do I confirm asystole is real?

Verify the patient is truly pulseless, confirm leads are connected and gain is up, and check a second lead — fine ventricular fibrillation can look like a flat line in one view.

What are the reversible causes?

The ACLS 'Hs and Ts' — hypoxia, hypovolemia, hydrogen ion (acidosis), hypo/hyperkalemia, hypothermia; tension pneumothorax, tamponade, toxins, thrombosis (pulmonary/coronary). The code team works these.

Asystole — an educational nurse reference.

The flat line that is not shockable — how to confirm it's real and why the response is CPR plus reversible causes.

Recognizing this rhythm at the bedside means matching pattern, intervals, and clinical context. This page covers the educational pattern; calipers and your clinical judgment carry it across the line.

What RN PocketPal does

Identifying traits

Rhythm: flat or nearly flat — no organized electrical activity.
No P waves, no QRS, no pulse.
NOT shockable: asystole and PEA are the non-shockable arrest rhythms.
Confirm in more than one lead to rule out fine VFib or a disconnected lead.

Verify with

Confirm the patient is pulseless and the leads are connected — a flat line can be a lead-off artifact.
Check a second lead: fine VFib can masquerade as asystole.
Follow ACLS: CPR + epinephrine + search for reversible causes (the Hs and Ts). Asystole is not shocked.

Who it’s for

For Nurses and nursing students learning rhythm interpretation.

Frequently asked questions

Is asystole shockable?: No. Asystole and PEA are non-shockable arrest rhythms. The response is high-quality CPR, epinephrine per ACLS, and aggressively treating reversible causes — defibrillation is not indicated.
How do I confirm asystole is real?: Verify the patient is truly pulseless, confirm leads are connected and gain is up, and check a second lead — fine ventricular fibrillation can look like a flat line in one view.
What are the reversible causes?: The ACLS 'Hs and Ts' — hypoxia, hypovolemia, hydrogen ion (acidosis), hypo/hyperkalemia, hypothermia; tension pneumothorax, tamponade, toxins, thrombosis (pulmonary/coronary). The code team works these.

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Reviewed by RN PocketPal Clinical Team, RN. Last reviewed June 4, 2026.