A 70 year old man with an implanted cardioverter/defibrillator is admitted to ICU following elective surgery. How does the device affect your management? What problems may be associated with the device?
The cardioverter/defibrillator is usually inserted for ventricular arrhythmias resistant to antiarrhythmics or where antiarrhythmics are contraindicated. The patients usually have severe LV dysfunction and this has its own implications. Batteries usually last for 5-7 years and AV pacing facility is included.
In routine elective surgery its presence should not effect the patient’s management greatly but it may have been switched off because of the interference from diathermy. Cardiac surgery may have displaced a lead or fractured a lead, there is a risk of lead or box infection if bacteraemia occurs and threshold may be changed by medications. It is important to check with the responsible technician and cardiologist for programming and idiosyncrasies of the unit and maintain ECG monitoring with external defibrillator available.
Problems that arise from the device include –
• Battery depletion
• Lead fracture or displacement
• Multiple shocks due to algorithm error, sensing failure, oversensing of physiological signals and lead failure
• EMF interference from shaver, TV remote, MRI are also possible.
Conditions which pose as indications for the insertion of an AICD are more threatening than the AICD itself, in my opinion.
Thus, the device itself affects ICU mangement only insofar as
There is a beautiful and freely available article by Pinski et al which lists not only the common AICD-related problems, but also the solutions to them. In brief, the following problems may be encountered:
Total device failure: there is no pacing or AICD activity. The device appears dead for all intents and purposes. There are several possible causes for this:
Pacing failure: the device seems to be working (pacing spikes are seen on ECG) but there is no capture. This usually means something has happened to its interface with the myocardium.
Failure to defibrillate VT or VF: the patient is clearly dying but the AICD for some reason refuses to rescue them. Why might that be? It is usually some sort of programing error. For instance:
Overenthusiastic defibrillation: the device is shocking the patient relentlessly.
Inappropriately normal function: the device missed the family conference, and does not realise the patient is being palliated. In these situations the AICD should be disabled. Ethical issues arise if the patient has an underlying complete heart block or something similar (in which you might want to merely disable the defib function).
Logistic consequences of having an implantable device: i.e. problems with having some implanted object, with or without intrinsic electrical activity.
Obscure problems not unique to AICDs but common to PPMs as well:
A bit of general information about the AICDs: DiMarco, John P. "Implantable cardioverter–defibrillators." New England Journal of Medicine 349.19 (2003): 1836-1847.
A more specific look at the problems they can cause: Pinski, Sergio L. "Emergencies related to implantable cardioverter-defibrillators."Critical care medicine 28.10 (2000): N174-N180.
GOULD, LAWRENCE, et al. "Pacemaker failure following external defibrillation." Pacing and Clinical Electrophysiology4.5 (1981): 575-577.
Gale, Christopher P., and Graham P. Mulley. "Pacemaker explosions in crematoria: problems and possible solutions." Journal of the Royal Society of Medicine 95.7 (2002): 353-355.
Monsieurs, Koenraad G., et al. "Semi-automatic external defibrillation and implanted cardiac pacemakers: understanding the interactions during resuscitation." Resuscitation 30.2 (1995): 127-131.
Nicholson, William J., Kathryn A. Tuohy, and Peter Tilkemeier. "Twiddler's syndrome." New England Journal of Medicine348.17 (2003): 1726-1727.