An implantable cardioverter-defibrillator (ICD) is a small device that is placed under the skin in the pectoral region. This device continuously monitors the patient’s heart rate and, if necessary, delivers an electric shock to restore the heart’s normal rhythm if a potentially fatal arrhythmia occurs.
How does an ICD work?
There are two types of ICDs:
- A transvenous ICD, the most common type. It consists of a pulse generator implanted under the skin, usually below the collarbone, and electrodes that are inserted into the veins to reach the heart chambers. These electrodes monitor the heart’s electrical activity and deliver shocks if dangerous arrhythmias are detected.
- A subcutaneous ICD, which is implanted under the skin below the armpit, but without inserting electrodes directly into the heart. The electrode is placed along the breastbone.
Some ICDs are combined with cardiac resynchronization therapy, which helps coordinate the contractions of the left and right ventricles in patients with heart failure. This improves cardiac function while also protecting against ventricular arrhythmias.
Why get an ICD?
An ICD is primarily recommended for patients at high risk of ventricular arrhythmias, especially those at risk of sudden cardiac death. ICDs are especially indicated for individuals with a history of heart conditions, particularly those caused by ventricular tachycardia or ventricular fibrillation, as they are at high risk of recurrence.
They are also advised for individuals with dilated or hypertrophic cardiomyopathies, when the heart muscle is abnormally enlarged or thickened, as they often have an increased risk of ventricular arrhythmias.
Patients with heart failure or those who have survived a myocardial infarction (heart attack) may also have an ICD implanted.
How is an ICD implanted?
To insert the ICD, a small incision is made under the collarbone, usually on the left side. If a transvenous ICD is used, the leads are inserted into a nearby vein and guided towards the heart using fluoroscopy, a type of X-ray. Once the electrodes are in place, they will be attached to the heart wall. The pulse generator is then connected to the electrodes and placed in the subcutaneous pocket created under the skin. It is then tested to ensure it correctly detects arrhythmias and delivers appropriate shocks or pacing.
Once the ICD is in place and tested, the incision is closed with sutures or staples, and a bandage is applied.
The patient is then transferred to a recovery room, where they are monitored for several hours to check for any immediate complications. Most patients can return home the same day or the next day, depending on their overall condition.
Is ICD implant surgery painful?
No, having an ICD implanted is a minimally painful procedure. The patient may experience some discomfort afterward due to the presence of the small device, but no actual pain.
What happens after the ICD implant procedure?
After the ICD implantation, the patient will need regular follow-up to ensure the device is functioning properly.
This follow-up will include regular appointments with the cardiologist, who will perform tests on the ICD to check the battery, electrode function, and the overall effectiveness of the device. These appointments will typically take place every three to six months. The cardiologist will examine the ICD, the information it contains and the history of its activity.
Some ICDs also feature a remote monitoring device that provides the cardiologist with regular information about the patient’s cardiac health.
What precautions should be taken?
Living with an ICD will require you to take some precautions, such as avoiding strong magnetic fields and certain medical equipment that may cause interference. Security gates at airports can also disrupt ICDs, although most devices are well-shielded against interference in normal situations.
Patients are also given a medical ID card indicating they have an ICD, which can be helpful in case of a medical emergency.
After the initial healing period, most patients can resume their normal activities, including physical exercise. However, contact sports and activities involving the risk of a blow to the implant area should be avoided. The cardiologist will provide specific advice based on the patient’s situation.
Patients should be informed that the ICD can deliver shocks to correct arrhythmia. Although these shocks may feel uncomfortable, they are essential for preventing cardiac arrest. If multiple shocks occur, or if a shock is followed by persistent symptoms such as chest pain or dizziness, the patient should seek immediate medical attention or go to hospital.
Reviewed and approved by Lyric Institute’s cardiac pacing team
