Implantable cardioverter defibrillator (ICD) failure

Last Updated on by frcemuser


If the patient is in cardiac arrest

  • Perform basic life support in accordance with current BLS/ALS guidelines
  • Avoid placing the defibrillator electrode over or within 5cm of the ICD generator site
  • If a shockable rhythm is present (VF or pulseless VT), but the ICD is not detecting it, perform external defibrillation
  • If the ICD is delivering therapy (whether by anti- tachycardia pacing or shocks) but is failing to convert the arrhythmia, then external defibrillation

If the patient is not in cardiac arrest. Determine whether an arrhythmia is present.

If no arrhythmia is present

  • If therapy from the ICD has been effective, the patient is in sinus rhythm or is paced, monitor the patient, give O2 and arrange a further assessment to investigate the possibility of new myocardial infarction (MI), heart failure, other acute illness or drug toxicity / electrolyte imbalance etc.
  • An ICD may deliver inappropriate shocks (i.e. in the absence of arrhythmia) if there are problems with sensing the cardiac rhythm or there are problems with the leads. Record the rhythm (with shocks if possible), disable the ICD with a magnet, monitor the patient and arrange a further assessment with help from the ICD centre. Provide supportive treatment as required.

If an arrhythmia is present:

  • If an arrhythmia is present and shocks are being delivered, record the arrhythmia (and shocks if possible) on the ECG. Determine the nature of the arrhythmia.
    • If the rhythm is supraventricular i.e. sinus tachycardia, atrial flutter, atrial fibrillation, junctional tachycardia, etc. and the patient is haemodynamically stable, and the patient is continuing to receive shocks, disable the ICD with a magnet. Consider possible causes, treat appropriately
    •  If the rhythm is ventricular tachycardia:
      • Pulseless VT should be treated as cardiac arrest 
      •  If the patient is haemodynamically unstable, and ICD shocks are ineffective, treat as per VT guideline.
      • An ICD will not deliver anti-tachycardia pacing (ATP) or shocks if the rate of the VT is below the programmed detection rate of the device. Conventional management may be undertaken according to the patient’s haemodynamic status.
      • Recurring VT with appropriate shocks. Manage any underlying cause (acute ischaemia, heart failure etc.). Sedation may be valuable. Disable ICD (apply magnet) ONLY if haemodynamically compromised.



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