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Asystole

Also called flatline.

A flat line with only slow baseline drift. Confirm it in a second lead and check leads, cables and gain before calling it. Not shockable: CPR and epinephrine.

A 6-second EKG rhythm strip showing Asystole.
Asystole, 6 seconds of strip. Each small box is 0.04 seconds and each large box is 0.20 seconds.

How to identify Asystole

Rate
None
Rhythm
None
P waves
None
PR interval
None
QRS
None
Clincher
A flat line. Confirm it in a second lead and check leads, cables and gain.

Rhythms it gets mistaken for

Treatment by certification level

Open your level. Treat the patient, not the strip.

Paramedic

Non-shockable arrest.

  • High-quality CPR. Never shock asystole or PEA.
  • Confirm asystole in a second lead first: fine V-fib or a loose lead can look flat.
  • Epinephrine 1 mg IV/IO as early as feasible, then every 3-5 minutes.
  • No antiarrhythmic: there is no rhythm for one to act on.
  • Hunt for the cause: the H's and T's.
  • Two-minute cycles with a rhythm check. If it turns shockable, switch to the shock path.
  • Waveform capnography. An abrupt rise in EtCO2 is often the first sign of ROSC.
AEMT

Cardiac arrest: CPR, the AED, epinephrine.

  • High-quality CPR and the AED, exactly as at the EMT level. After every analysis, shock or no shock, compressions resume immediately.
  • IV or IO access.
  • Epinephrine 1 mg IV/IO as early as feasible, then every 3-5 minutes.
  • Supraglottic airway and waveform capnography. EtCO2 under 10 mmHg means fix the compressions; an abrupt sustained rise suggests ROSC, confirmed at the scheduled rhythm check.

Manual defibrillation and antiarrhythmics (amiodarone, lidocaine) are Paramedic level. The AEMT's electrical therapy is the AED.

EMT

Cardiac arrest: CPR and the AED.

  • High-quality CPR, starting with compressions.
  • AED on as soon as it arrives.
  • The AED will not advise a shock for this rhythm. Resume compressions immediately.
  • Two minutes of CPR, then let the AED reanalyze. Check a pulse only at that scheduled rhythm check.

Could you pick out Asystole on a fresh strip? See how many rhythms you can identify in one minute.

Try the 60-second rhythm challenge