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Implantable Cardioverter Defibrillator Complications

Surgical and post-surgical complications with ICDs


Updated November 13, 2011

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

While implantable cardioverter defibrillators (ICDs) are extremely effective and generally quite safe, it is possible for you to experience complications with your ICD system. These ICD complications fall into two types: surgical complications, and post-surgical complications.

Surgical Complications

The main risks related to ICD implantation surgery include:
  • bleeding
  • infection
  • collapsed lung
  • damage to the heart or to a blood vessel
The overall risk of having any of these complications is around 2 to 3%. The risk of actually dying from an ICD implantation procedure is very low - in most people, well under 1%.

Most of the surgery-related complications end up being relatively minor and relatively easily treated. The major exception to this general "rule" is infection. If the ICD becomes infected, then the entire ICD system (the ICD generator and all the leads) usually must be removed in order to successfully cure the infection with antibiotics - and once the infection is cleared up, another ICD system will need to be implanted.

You will be exposed to these same surgical risks each time your ICD generator needs to be replaced (roughly every 6 to 7 years, when the battery begins to wear out). Your risk from this replacement surgery is generally lower than for the initial surgery. This is because the replacement surgery usually requires only replacement of the ICD generator itself, and not the ICD leads, which reduces to nearly zero the risk of collapsed lung, and of damage to the heart or blood vessels. However, there is some evidence that the risk of infection is higher with replacement surgery than with the initial surgery.

Post-Surgical Complications

Post-surgical complications of ICD therapy include:
  • lead complications such as lead "dislodgement"(movement of the leads out of their proper position) or lead fracture, which can cause loss of effectiveness of the ICD system, or inappropriate shocks (see below)
  • movement of the ICD generator out of its proper position, which can cause pain, skin erosion or bleeding
  • inappropriate shocks, which cause pain, and can produce psychological trauma
The most common of these complications are inappropriate shocks. ICD shocks hurt. While the shocks are designed to be delivered only when a life-threatening arrhythmia occurs, about 20% of people with ICDs at one time or another will receive shocks for other reasons - so-called "inappropriate" shocks. These inappropriate shocks can be caused by any very rapid heart rhythm such as atrial fibrillation, or by the rapid heart rate that you get from strenuous exercise.

Preventing further inappropriate shocks depends on what is causing them. If an inappropriate shock occurs due to atrial fibrillation or exercise, in most cases the doctor can "re-program" the ICD to reduce the chance of further inappropriate shocks. But preventing inappropriate shocks caused by an ICD lead problem usually requires a surgical procedure.

Finally, complex, implantable electronic devices such as ICDs and pacemakers can occasionally fail to operate appropriately. If this happens, the ICD may not be able to deliver therapy when it is needed, or it may deliver inappropriate shocks. An ICD that fails to function normally almost always needs to be removed and replaced with a new device.

Fortunately, the large majority of people who have ICDs never experience any serious complications with their devices.

Read More About ICDs:


Maisel, WH, Moynahan, M, Zuckerman, BD, et al. Pacemaker and ICD generator malfunctions: analysis of Food and Drug Administration annual reports. JAMA 2006; 295:1901.

Ellenbogen, KA, Wood, MA, Shepard, RK, et al. Detection and management of an implantable cardioverter defibrillator lead failure: incidence and clinical implications.J Am Coll Cardiol 2003; 41:73.

Maisel, WH. Pacemaker and ICD generator reliability: meta-analysis of device registries. JAMA 2006; 295:1929.

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