Help the development of the site, sharing the article with friends!

Cardioverter-defibrillator (ICD) is a device that has become an important element in the prevention of sudden cardiac death in patients from the highest risk groups. What are the indications for the implantation of a cardioverter-defibrillator? What is the procedure? What is allowed and what is not allowed for ICD-implanted people?

Cardioverter-defibrillator(EnglishImplantable Cardioverter Defibrillator , ICD) has become an important element in the prevention of sudden cardiac death in patients from the highest risk.Cardioverter-defibrillatorcombines the function of electrostimulation with the so-called high energy therapy, i.e. when a sudden, life-threatening ventricular arrhythmia (e.g. ventricular tachycardia, ventricular fibrillation) occurs, the device sends moderate shocks, thus saving the patient's life.


  1. Cardioverter-defibrillator (ICD): what is it?
  2. Cardioverter-defibrillator (ICD): how does it work?
  3. Cardioverter-defibrillator (ICD): indications for use
  4. Cardioverter-defibrillator (ICD): implantation procedure
  5. Cardioverter-defibrillator (ICD): when to replace?

Cardioverter-defibrillator (ICD): what is it?

The cardioverter defibrillator is an electronic device the size of a matchbox. Originally, this device, constructed by a Polish doctor, Mieczysław Mirowski, was implanted into the patient's chest, and the procedure was performed by cardiac surgeons.

- Currently, the most common form of ICD resembles a pacemaker and consists of an electrode (or electrodes) inserted into the heart, whose task is to sense the heart's own impulses and deliver "therapy" in life-threatening situations, and connected to the electrode, implanted under the the skin of the can housing the battery and electronic systems (minicomputer). Such a device may also act as a starter. Another device that performs the same task is the fully subcutaneous cardioverter defibrillator S-ICD.

Unlike the classic ICD, the electrode of this device does not come into contact with the heart and is implanted in the subcutaneous tissue near the sternum. S-ICD can interrupt an arrhythmia but cannot stimulate the heart. Today, implantation procedures are performed by operators - cardiologists-electrophysiologists - explains Sokalfrom the Laboratory of Electrophysiology and Heart Stimulation of the Silesian Center for Heart Diseases in Zabrze, member of the Heart Rhythm Section of the Polish Society of Cardiology.

Cardioverter Defibrillator (ICD) is effective in terminating ventricular tachycardia and fibrillation.

Cardioverter-defibrillator (ICD): how does it work?

The implantable cardioverter defibrillator "watches" the heart rhythm all the time. When the heart rate is higher than the predetermined and programmed by the doctor (higher than the so-called detection threshold), the device begins to analyze the characteristics of the ECG, trying to determine whether it is actually dealing with a life-threatening ventricular arrhythmia. It uses various algorithms for this purpose. Their task is to distinguish severe ventricular arrhythmias from physiological acceleration of the heart rate or less severe supraventricular arrhythmias.

"Detection threshold" can be individually programmed for each patient. Young people who engage in physical exertion leading to an increase in heart rate or people with known supraventricular arrhythmias such as atrial fibrillation tend to have a higher "detection threshold".

- If the ICD classifies the arrhythmia as life-threatening, it begins to prepare for termination, that is, delivery of therapy. The therapy may take the form of electric shock (cardioversion and defibrillation) or so-called anti-tachyarrhythmic stimulation (ATP), which involves short-term pacing of the ventricle at a rate slightly above the arrhythmia rate. What type of therapy will be delivered first is programmed by the doctor each time depending on the individual needs of the patient - says Dr. Adam Sokal.

Cardioverter-defibrillator (ICD): indications for use

  • sudden cardiac arrest patients,
  • heart failure patients with ejection fraction (LVEF) ≤ 40% who have had an episode of severe ventricular arrhythmia (hemodynamically unstable ventricular tachycardia or with syncope),
  • patients with post-infarction (ischemic) heart failure in NYHA class II / III with low LVEF ≤ 35%, at least 40 days after myocardial infarction,
  • patients with heart failure in NYHA class II / III, LVEF ≤ 35%, with low ejection fraction without ischemic heart disease (dilated cardiomyopathy).

The indications are subject to additional conditions: optimal pharmacotherapy, expected survival in good functional condition over 1 year. The final decision about implanting this device is made by the cardiologist after executiona complete set of relevant tests.

Cardioverter-defibrillator (ICD): driving restriction

Type of sudden cardiac death preventionPrivate driverProfessional driver
ICD implantationprimary1 monthpermanent
secondary3 monthspermanent
ICD replacementprimary1 weekpermanent
secondary1 weekpermanent
Replacing the ICD electrodeprimary1 monthpermanent
secondary1 monthpermanent
Type of ICD therapyPrivate driverProfessional driver
ICD therapyadequate3 monthspermanent
inadequateuntil the problem of inadequate therapies is resolvedpermanent

Good to know: Safe driver with a cardioverter-defibrillator. Can I drive with an ICD?

Cardioverter-defibrillator (ICD): implantation procedure

ICD implantation is usually performed under local anesthesia. Rarely, for example in children, the procedure is performed under general anesthesia.

Most patients rate the procedure as little painful (2-3 on a 10-point scale, with 10 being the maximum pain). Sometimes, at the patient's request, painkillers may be administered during the procedure.

At the end of the procedure, your doctor may decide to perform a so-called defibrillation test (DFT test). Its task is to confirm that the implanted device is working properly. The DFT test is performed under short-term general anesthesia (the patient is put asleep for the test). If the procedure is not accompanied by complications, the patient's stay in hospital for the ICD implantation procedure does not exceed 2-3 days. Complications are rare, but if they do occur, they prolong hospitalization.

- Post-operative sutures are usually removed between the 7th and 10th day. Depending on the center, the patient should report for a check-up and final programming of the device between 1 and 3 months after implantation. During this period, sudden arm movements on the side where the device is implanted should be avoided. You also have to give up drivingcar. Of course, it is necessary during this period to carefully observe the wound and report any unusual reactions to doctors. There may be: slight swelling, bruising or soreness that lasts for one to two months. After this period, the patient should not feel any discomforts related to the implanted device - explains Dr. Adam Sokal.

Cardioverter-defibrillator (ICD): when to replace?

The cardioverter defibrillator must be replaced when the battery is depleted. Very high consumption of the battery occurs during shocks, when the patient has, for example, an electric storm, i.e. 3 or more discharges per day. During such a sudden, severe, and life-threatening arrhythmia, the device can wear out very quickly - within days or even hours.

- It may take up to 10 years between implantation and replacement of the ICD, but this period may be significantly shortened in the presence of high-energy interventions of the implanted ICD. During this time, the patient should come for a check-up at least once every at least 6 months or once a year if he is subject to telemetry on a daily basis. Unfortunately, such a much more convenient and safer method of control for patients, unlike in other European countries, is not reimbursed in Poland. In practice, only a few patients can use it. If necessary, the "box" of the device containing the battery is replaced. The procedure itself is shorter than the implantation, but still requires 2-3 days of hospitalization - says Dr. Adam Sokal.

Electrical storms can lead to severe depression and anxiety disorders, which in extreme cases resemble post-traumatic stress disorder.

What is allowed and what is not allowed for people with ICDs?

After the implantation of the ICD and the healing of the wound after implantation, the patient is usually not subject to more restrictions than those resulting from the disease that caused the implantation.

The patient may drive the car unless high energy interventions are frequent. ICD implantation is also not a reason to restrict professional activity in most cases, although some professions such as co-driver or professional driver are not recommended for ICD patients.

A patient with an implanted cardioverter-defibrillator can practice amateur sports, but should inform the doctor about it so that he can program the device properly. Martial arts are not recommended.

There are no restrictions on the use of standard household and electronic devices, including mobile phones. Where it occurs in the environmentwork of high electromagnetic field intensities, it is necessary to consult a doctor first, and sometimes to perform detailed measurements.

As some medical procedures are not recommended for patients with ICD, always inform the physician who recommends the procedure that you have an implanted device. In the past, it was completely contraindicated to perform magnetic resonance imaging in patients with ICD. In modern devices it is possible, but it is subject to certain limitations and requires appropriate reprogramming of the ICD.

Help the development of the site, sharing the article with friends!