Atrial paced rhythm
A narrow vertical pacer spike immediately precedes each P wave: the pacemaker is starting the beat in the atria, and the impulse then conducts down the normal pathway. Normal PR and a narrow QRS follow, so the only tell is the spike in front of every P.
How to identify Atrial paced rhythm
- Rate
- The set pacing rate
- Rhythm
- Regular
- P waves
- Upright, one before every QRS, each right after a pacer spike
- PR interval
- 0.12-0.20 s, constant
- QRS
- Under 0.12 s
- Clincher
- A pacer spike immediately before every P wave, then a normal PR and a narrow QRS.
Rhythms it gets mistaken for
Atrial paced rhythm vs Ventricular paced rhythm
Atrial paced rhythm has a pacer spike right before every P wave. With a ventricular paced rhythm you would see a pacer spike right before every wide QRS. It also has one upright P wave before every QRS, all the same shape, while a ventricular paced rhythm would show no upright P wave in front of the QRS. It also has a narrow QRS, under 0.12 s, while a ventricular paced rhythm would show a wide QRS, 0.12 s or more. A narrow QRS means the signal came from above the ventricles. How to spot a ventricular paced rhythm: A pacer spike immediately before every wide QRS.
Atrial paced rhythm vs Normal sinus rhythm
Atrial paced rhythm has a pacer spike right before every P wave. With normal sinus rhythm you would see no pacer spikes. A pacemaker starts every beat in the atria, and the impulse conducts down the normal pathway. How to spot normal sinus rhythm: Every step of the six-step read is normal.
Atrial paced rhythm vs 1st-degree AV block
Atrial paced rhythm has a pacer spike right before every P wave. With 1st-degree block you would see no pacer spikes. It also has a normal PR interval of 0.12-0.20 s, while 1st-degree block would show a PR interval over 0.20 s that is the same on every beat, with no dropped beats. A pacemaker starts every beat in the atria, and the impulse conducts down the normal pathway. How to spot 1st-degree block: Every P conducts, just late. Nothing drops.
Treatment by certification level
Open your level. Treat the patient, not the strip.
Paramedic
Confirm the pacemaker is doing its job.
- Atrial capture: a P wave after every spike, then the patient's own narrow QRS through the normal pathway. Mechanical capture: a pulse to match.
- Failure to sense: spikes landing on the patient's own beats. Failure to capture: spikes with no P wave 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.