Definition and Overview

Implantable cardioverter defibrillators (ICDs) are devices used to treat severe abnormal heart rhythms. They are implanted in the chest or abdomen. ICDs deliver shocks or electrical pulses to the heart when it beats either too slowly or too fast. By doing so, they help prevent heart failure and sudden cardiac arrest (SDA). SDA is a condition in which the heart stops beating. As a result, the blood flow to the rest of the body is stopped. This can cause vital organs to die in a matter of minutes.

Although ICDs are life-saving devices, they can put patients at risk of serious complications if they malfunction. Any part of the ICD system can become dislodged. The ICD may also fire shocks even when they are not needed. Other risks include pain and bleeding. Other more serious ICD-related problems are:

  • Infection at the area where the device was placed

  • Damage to nearby blood vessels and nerves. The device can also cause damage to the heart.

  • A collapsed lung - This is one of the possible complications of ICD surgery.

  • ICD failure, or when the device fails to deliver shocks when needed – This puts patient at risk of heart failure and SDA.

Causes of Condition

The placement of ICDs requires a minor surgery. It involves threading lead wires through a blood vessel to reach the heart. Once in place, the ICD generator is implanted under the skin. The lead wire is then attached to the generator.

ICD-related complications can be caused by the surgery. Because the procedure requires an incision, there is a risk of bleeding and infection. There is also a risk of damage to surrounding blood vessels and the heart. Another complication of the surgery is a collapsed lung. This condition occurs when a hole develops in the lung. This hole can allow air or gas to build up in the area between the chest wall and the lung. Surgery-related complications are often minor and can be easily treated.

Post-surgical complications, on the other hand, are often related to how well the device is working. The lead wire or the generator can move out of its position. When this happens, the ICD system will lose its ability to detect slow or fast heartbeats. It can also cause the system to fire shocks even when they are not needed. In addition, this may cause bleeding and pain in the area where the system was placed.

Key Symptoms

Symptoms of the condition may include:

  • Bleeding - This can occur if the ICD system is dislodged or as a complication of surgery.

  • Inappropriate shocks - Based on studies, this complication occurs in about 8.5% of all patients with ICDs.

  • Infection - This may occur if pathogens enter the body through the incision made during surgery. It can also occur if the patient has an allergic reaction to the ICD system.

  • Lead fracture - This is one of the main causes of ICD system failure. It can to lead to over-sensing, which can cause the generator to fire shocks even when they are not needed.

  • Pain - Some patients may experience chest pains.

  • Wound dehiscence - This can be caused by a number of factors. These include trauma to the wound after surgery, certain medical disorders, and the surgeon’s lack of enough experience.

  • Failure of the device - This can result in heart failure and SDA.

Who to See and Types of Treatments Available

Patients with ICD-related problems are treated by a cardiologist (heart specialist).

Problems caused by ICD surgery are often caught and managed before the patient is discharged from the hospital. Patients are monitored for any signs of problems after the procedure. This allows surgeons to correct them before the patient is sent home. Below are some of the possible complications and how they are managed:

  • Infection - This is treated with antibiotics. In severe cases, the ICD system may need to be replaced. Patients undergoing surgery to replace their ICD are still at risk of infection.

  • Inappropriate shocks - Patients who are getting inappropriate shocks are advised to return to their doctor. Their ICD system may need to be reprogrammed to correct the problem.

  • ICD malfunction - The ICD system may fail to deliver shocks when needed. This can be caused by lead fracture or accidental deactivation of the generator. In such cases, patients may be temporarily placed on drug therapy to stabilise their heart rhythm. They may also need to undergo another surgery to have their ICD replaced.

  • Lead fracture - If the lead has failed or stopped working properly, the surgeon may have it removed and replaced. There is also an option to keep it in place and just add another lead. The surgeon will decide on the best method depending on the patient’s circumstances.

Although many ICD-related problems can be corrected, the preferred approach is to prevent them from occurring. This is the goal of ICD follow-ups, which are scheduled as soon as a week after the surgery. Doctors ensure that the wound is healing properly and that the patient has not developed infections and other surgery-related complications.

All patients with ICDs must see their doctor for follow-up care at least once every six months. During these follow-ups, the device is checked to make sure that it is working properly. Its battery is also checked. The doctor will also analyse any activity recorded by the device. This allows the doctor to see if the device responds well to abnormal heart rhythms. If necessary, the ICD system is re-programmed to achieve optimal results.


  • The Antiarrhythmics versus Implantable Defibrillators (AVID) Investigators. A comparison of antiarrhythmic-drug therapy with implantable defibrillators in patients resuscitated from near-fatal ventricular arrhythmias. The Antiarrhythmics versus Implantable Defibrillators (AVID) Investigators. N Engl J Med. 1997 Nov 27. 337(22):1576-83.

  • Moss AJ, Hall WJ, Cannom DS, et al. Improved survival with an implanted defibrillator in patients with coronary disease at high risk for ventricular arrhythmia. Multicenter Automatic Defibrillator Implantation Trial (MADIT) Investigators. N Engl J Med. 1996 Dec 26. 335(26):1933-40.

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