ECG rhythms Ventricular and arrest rhythms
Ventricular fibrillation ECG
Ventricular fibrillation. Chaotic, irregular deflections of varying size with no identifiable QRS complexes, in a pulseless patient.
A 30-second recording of the heart model, played in real time. Run live starts the engine itself with this rhythm.
Computed by the TracingsMD heart model (Junkers engine): simulated for education, not a patient recording and not for diagnosis.
Measured on this recording
No QRS complexes: rate and intervals cannot be measured in this rhythm.
What it is
Chaotic, disorganized electrical activity of the ventricles with no effective contraction: there is no pulse and no cardiac output. Without treatment it is fatal within minutes.
How to read this strip
| Rate | No measurable rate. |
|---|---|
| Rhythm | Chaotic. |
| P waves | None. |
| PR | None. |
| QRS | No identifiable QRS complexes. |
| QT | None. |
Causes
- Acute ischemia and myocardial infarction (most common).
- Scar and cardiomyopathy.
- Electrolyte disturbance, drug toxicity.
- Long QT, Brugada syndrome.
- Electrocution, hypothermia, commotio cordis (a sudden blow to the chest).
What to consider
- Confirm cardiac arrest, start high-quality CPR and defibrillate as soon as possible.
- Follow the adult cardiac arrest algorithm: shock, two minutes of CPR, rhythm check; epinephrine after the second shock (then every 3–5 minutes) and amiodarone or lidocaine after the third, per protocol.
- Look for the reversible causes (the Hs and Ts: hypoxia, hypovolemia, hydrogen ion excess, hypo- or hyperkalemia, hypothermia, tension pneumothorax, tamponade, toxins, thrombosis).
- Loose electrodes and movement can mimic VF: a patient in VF is unresponsive and pulseless.
Key point
VF is treated by defibrillation; every minute without a shock lowers the chance of survival, so keep compressions going until the shock is ready.
Not to be confused with
- Torsades de pointes — Torsades has discrete wide QRS complexes whose height waxes and wanes. Here no QRS complex can be identified.
- Asystole — There is clear electrical activity; asystole is a flat line.
- Sinus rhythm with motion artifact — With artifact, regular QRS complexes still march through the noise. None are present here.