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Ventricular paced rhythm

Also called pacemaker rhythm.

A narrow vertical pacer spike immediately precedes each wide QRS: the pacemaker, not the AV node, is depolarizing the ventricle. Electrical capture is a wide complex after every spike; mechanical capture is a pulse to match.

A 6-second EKG rhythm strip showing Ventricular paced rhythm.
Ventricular paced rhythm, 6 seconds of strip. Each small box is 0.04 seconds and each large box is 0.20 seconds.
Try the 60-second rhythm challenge →

How to identify Ventricular paced rhythm

Rate
The set pacing rate
Rhythm
Regular
P waves
None here (the ventricle is paced)
PR interval
None
QRS
Wide, right after each spike
Clincher
A pacer spike immediately before every wide QRS.

Rhythms it gets mistaken for

  • Ventricular paced rhythm vs Atrial paced rhythm

    Ventricular paced rhythm has a pacer spike right before every wide QRS. With an atrial paced rhythm you would see a pacer spike right before every P wave. It also has no upright P wave in front of the QRS, while an atrial paced rhythm would show one upright P wave before every QRS, all the same shape. It also has a wide QRS, 0.12 s or more, while an atrial paced rhythm would show a narrow QRS, under 0.12 s. A wide QRS means the signal started in the ventricles or got there through an abnormal path. How to spot an atrial paced rhythm: A pacer spike immediately before every P wave, then a normal PR and a narrow QRS.

  • Ventricular paced rhythm vs Idioventricular rhythm

    Ventricular paced rhythm has a pacer spike right before every wide QRS. With an idioventricular rhythm you would see no pacer spikes. A pacemaker starts every beat. How to spot an idioventricular rhythm: Wide, slow, no P waves: the ventricle escaping on its own.

  • Ventricular paced rhythm vs 3rd-degree (complete) AV block

    Ventricular paced rhythm has a pacer spike right before every wide QRS. With 3rd-degree block you would see no pacer spikes. It also has no upright P wave in front of the QRS, while 3rd-degree block would show regular P waves, with more P waves than QRS complexes. A pacemaker starts every beat. How to spot 3rd-degree block: Two rhythms that ignore each other: AV dissociation.

Treatment by certification level

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

Paramedic

Confirm the pacemaker is doing its job.

  • Electrical capture: a wide QRS after every spike. Mechanical capture: a pulse to match.
  • Failure to sense: spikes landing on the patient's own beats. Failure to capture: spikes with no complex after them. Failure to pace: no spikes when there should be.
  • If you defibrillate, keep the pad at least 1 inch from the implanted device, and never withhold a shock because of it.
AEMT

Pulse present and stable.

  • Oxygen only if hypoxic or short of breath, IV access, monitoring.
  • Acquire and transmit a 12-lead ECG. Interpreting it is a Paramedic skill.
  • Transport and reassess. Request a paramedic if the patient worsens.
EMT

Pulse present: assess and support.

  • Treat the patient, not the rhythm name: airway, breathing, circulation, vital signs.
  • Oxygen if the SpO2 is under 94%, the patient is short of breath, or shows signs of shock.
  • Request ALS and transport promptly. Reassess on the way.

An AED goes only on a patient who is unresponsive, not breathing and pulseless. It cannot feel a pulse, so on a patient with a pulse it can advise a shock that would do harm.

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

Try the 60-second rhythm challenge