cardiolab logocardiolab

Asystole

critical
Lead II
25 mm/s10 mm/mV
Heart rate
—
RR
—
QT
—

Asystole

Complete absence of electrical activity in the heart. One of the four cardiac arrest rhythms (VFib, pulseless VTach, PEA, Asystole). Represents total cardiac standstill with no mechanical or electrical function.

Mechanism

Complete absence of electrical activity in the heart. One of the four cardiac arrest rhythms (VFib, pulseless VTach, PEA, Asystole). Represents total cardiac standstill with no mechanical or electrical function.

Findings· 3
  • Flatline on monitor — no P waves, QRS complexes, or T waves.
  • May show subtle baseline drift or artifact.
  • Must confirm in at least 2 leads to rule out equipment failure, loose leads, or fine VFib masquerading as asystole.
Clinical Impact

Cardiac arrest with poorest prognosis. Requires immediate high-quality CPR and epinephrine. Do NOT defibrillate asystole. Identify and treat reversible causes (H's and T's). Survival <2% in out-of-hospital arrest.

Differential· 1
Fine Ventricular Fibrillation

Very fine VFib can mimic flatline. Confirm in ≥2 leads before calling asystole.