In idioventricular rhythm the ventricles set the pace on their own because the higher pacemakers have failed or slowed, giving wide QRS complexes at 20 to 40 beats per minute. An accelerated form at 40 to 100 beats per minute often appears after coronary reperfusion and is usually harmless.
Key symptoms
- Often none when the rhythm is accelerated
- Dizziness, weakness or fainting when the rate is slow
- Chest pain from an underlying heart attack
- Confusion or shortness of breath from low output
What you find on exam
- Slow, regular pulse
- Perfusion: blood pressure, skin, mental status, urine output
- Signs of heart failure or shock
- Medication review: digoxin and other drugs that slow the heart
Tests
- 12-lead ECG: wide QRS, regular rhythm, no related P waves
- Troponin for ischemia
- Potassium, magnesium and other electrolytes
- Digoxin level if the patient takes it
Treatment basics
- Accelerated rhythm after reperfusion: monitor, usually no treatment
- Never suppress it with antiarrhythmics such as lidocaine, since it may be the only rhythm
- Slow rhythm with poor perfusion: atropine, then transcutaneous pacing or a dopamine or epinephrine infusion
- Treat the cause: ischemia, electrolytes, drug toxicity
Red flags
- Rate under 40 with low blood pressure or altered mental status
- No pulse with an organized rhythm on the monitor: treat as cardiac arrest
- Ongoing chest pain or ECG signs of infarction
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.