Transthoracic cardiac pacing

 

Guideline describing the indications, contraindications, procedure and complications of transthoracic cardiac pacing

 

Indications

  • Patient with symptomatic bradycardia and a palpable pulse who has not responded to pharmacological therapy.
  • High-grade AV blockade
  • Cardiac arrest with ventricular standstill, but atrial activity present.

 

Contraindication

  • Asystolic cardiac arrest.

 

Procedural Technique

  • Provide supplemental oxygen and gain IV access
  • Some patients may require sedation to tolerate the discomfort associated with pacing, especially if higher currents are needed.
  • Ensure skin is clean, dry and shaven to allow electrical contact.
  • Sandwich the heart between an anterior electrode (placed over the precordium to the left of the sternum) and a posterior electrode (placed between the left scapula and the vertebral column). Ventricular pacing can also be done using standard pad placement as per defibrillation.
  • Set the defibrillator to ‘Pacing’ mode—once the pacing option is activated, ensure the monitor is sensing any intrinsic QRS complexes, signaled by a marker on the monitor.
  • Select the pacing rate: usually 60–80 beats/min.
  • Select current: start at 5 mA and increase in increments of 5 mA until electrical capture is visible on the ECG monitor. Capture generally occurs at 50–80 mA.
    • As the current rises and electrical capture with a ventricular contraction occurs, the monitor will start to show QRS–T complexes after each pacing spike.
  • Check that mechanical capture is also occurring by palpating the patient’s pulse.
  • Set the current at least 5 mA above the minimum current at which capture occurs.

 

Complications

  • Failure to capture.
  • Patient discomfort, so ensure adequate analgesia and sedation.
  • Failure to recognize fine VF because of the size of pacing artefact on the ECG screen. Palpate the pulse and or look for loss of signs of life.
  • Induction of other arrhythmias.
  • Potential for local cutaneous injury with prolonged use.

 

Date implemented – 05/2009
Review date – currently being revised
Author – Mike Cadogan

 

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