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Transcutaneous pacing (TCP) is a rapid, non-invasive method of providing temporary cardiac pacing in bradyarrhythmias.
The technique poses no electrical risk to staff, and complications are rare. See the ALS Bradycardia Algorithm.
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ℹ️ About
- TCP delivers external electrical impulses via defibrillator pads to stimulate ventricular contraction.
- Capture rates vary widely (10–93%) and depend on electrode placement, chest anatomy, and skin impedance.
- It can be life-saving, but skeletal muscle stimulation often causes severe discomfort, so sedation/analgesia is recommended if the patient is conscious.
- Primarily a bridge to transvenous pacing or definitive therapy.
Method
- Apply defibrillator pads in pacing mode:
- Preferred position: one pad anteriorly over the cardiac apex (V3 location), the other posteriorly under the left scapula.
- Alternative: anterior–sternal placement (as in defibrillation).
- Keep pads away from implanted devices (pacemakers/ICDs) and remove drug patches.
- Prepare skin: shave excess hair, dry the skin for optimal contact.
- Administer sedation and analgesia (e.g. IV Midazolam, Morphine) as tolerated.
- Select pacing mode (synchronous) to reduce risk of “R-on-T” ventricular fibrillation.
Settings
- Output current: Start low and titrate (20–120 mA typical; occasionally up to 200 mA).
- Pulse duration: 20–40 ms.
- Rate: Usually set to 60–80 bpm (commonly ~70 bpm).
- Gradually increase output until capture achieved (visible paced QRS complexes).
- Confirm capture:
- Pacer spike immediately followed by a broad QRS and T wave.
- Check for a corresponding palpable pulse (mechanical capture).
- Continue monitoring BP, SaO₂, and clinical status.
- Provide ongoing pain relief as needed.
- CPR can be performed concurrently if necessary.
Clinical Pearls
- TCP is rapid but uncomfortable: it stimulates skeletal muscle as well as myocardium.
- Always reassess for reversible causes of bradycardia (e.g. drugs, hypoxia, hyperkalaemia).
- Failure of capture should prompt pad repositioning, higher output, or consideration of transvenous pacing.
- In exams, key phrases: “bridge to definitive pacing” and “painful in awake patients.”
