ICD – implantable high-powered guardian angel

A cardioverter-defibrillator (ICD) implanted in patients at high risk of sudden cardiac arrest will alert and intervene in the event of a life-threatening ventricular arrhythmia. How the life-saving device works, how to prepare for the procedure, does life look different after implantation? These questions are answered by Dr. hab. med. Adam Sokal of the Heart Rhythm Section of the Polish Society of Cardiology.

What is an ICD?

– Implantable cardioverter defibrillator (ICD). Implantable Cardioverter Defibrillator (ICD) is a fully automatic device thatorgo task of detecting life-threatening ventricular arrhythmias and interrupting them. Originally developed by Mieczyslaw Mirowski, a Polish-born doctor, this device was implanted in the patient’s chest. 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, whichor which are tasked with sensing the impulseoin their own heart and delivering „therapy” in life-threatening situations, and connected to the electrode, implanted under the scohand of the can that holds the battery and electronics (minicomputer). Such a device can perform rot he function of the pacemaker. Another device that performs the same task is a completely subscoThe new S-ICD cardioverter defibrillator. In the rroUnlike a classic ICD, the electrode of this device is not in contact with the heart and is implanted into the subcutaneous tissue of theornej close to the sternum. The S-ICD can interrupt an arrhythmia, but cannot pacing the heart. Today, implantation procedures are carried out by operators – cardiologists-electrophysiologists.

How the cardioverter defibrillator works?

– Implantable cardioverter defibrillator all the time „observes” heart rhythm. If the heart rate is higher than the previously assumed and programmed by the doctor (higher than the „detection threshold”), the device begins to analyze ECG features, prodetermining whether a life-threatening ventricular arrhythmia is actually present. This uses rodifferent algorithms. Their function is to deomending dangerous ventricular arrhythmias from physiological acceleration of heart rate or less dangerous supraventricular arrhythmias. „Prog detection” can be individually programmed for each patient.

– In young people whoorych we expect them to be able to undertake physical exertion, ktory leads to acceleration of heart rate or in osob with known supraventricular arrhythmias, such as atrial fibrillationow, as a rule, a higher prog detection. If the ICD classifies an arrhythmia as life-threatening, it begins to prepare to terminate it, i.e., to deliver therapy. Therapy can take the form of an electrical shock (cardioversion and defibrillation) or so-called antitachyarrhythmic pacing (ATP), whichora relies on the bloodotkotot permanently pacing the ventricle at a rate slightly higher than the arrhythmia rate. Which type of therapy will be delivered first is programmed by the physician each time, depending on the individual needs of the patient. Our patients often call the ICD their angel strothat – Indeed, it is a high-powered angel!

When the decision is made to implant an ICD?

– Implantable cardioverter defibrillator implants (implants) patients whooThose who have survived cardiac arrest (i.e., have been successfully resuscitated) and the cause of the cardiac arrest is irreversible or uncontrollable. This is known as wt preventionorna. Since only one in four people survive cardiac arrest, ICDs are implanted roAlso for patients in whom theorych there is a high risk of cardiac arrest. This is known as primary prevention. In primary prevention, ICDs are most often implanted in patients after a heart attack, in whom theorychiatric patients whose left ventricular function (so-called left ventricular ejection fraction -EF is less than 35 percent) remains significantly impaired despite proper treatment.). Similarly, implantation of an ICD is required for patients in whom theorych there was damage to the left ventricle due to other causes (EF ≤ 35 percent.) and patients with congenital diseases, in whom theorych in the immediate family had a history of sudden death, regardless of left ventricular function.

How long the procedure takes and how to prepare for it?

ICD implantation is usually performed under local anesthesia – It is not necessary to put the patient to sleep. Rarely, for example, in children, the procedure is performed under anesthesia ogolnym. Most patientsow assesses the procedure as not very painful (2-3 on a 10-point scale, where 10 means maximum bol). Occasionally, at the patient’s request, anti-biotics may be administered during the procedureolowe. After the procedure, the doctor may decide to perform a so-called defibrillation test (DFT test). Its task is to confirm whether the implanted device is working properly. The DFT test is performed in the crottemporary anesthesia ogolnym (the patient is put to sleep for the test). If the procedure is not accompanied by complications, the patient’s stay in the hospital associated with ICD implantation does not exceed twooch-three days. Complications are rare, but if they occur, they cause prolonged hospitalization.

What you should pay attention toocient attention after the procedure?

The sutures after the procedure are generally removed between the siodm to the tenth day. Depending on the center, the patient should come in for follow-up and final programming of the device between the first and third months after implantation. During this period, sudden movements should be avoidedoin the arm on the side where theoIf necessary, the battery containing the device is replaced. It is necessary to roalso give up driving. Of course, it is necessary during this period to carefully observe the wound and report any unusual reactions to the doctorsow. The following may occur: a small, persistent one to twooch months swelling, bruising or soreness. After this period, the patient should not experience any discomfort related to the implanted device.

How many years „lives” ICD?

Up to 10 years may elapse between ICD implantation and replacement, but this period may be significantly shortenedocation if there are high-energy interventions of the implanted ICD. During this time, the patient should report for follow-up at least once every six months or once a year, in case he is subject to telemetry monitoring on a daily basis. Unfortunately, such a much more comfortable and safer for the patientoin sposob follow-up, in odrounlike in other countriesow European is not reimbursed in Poland. In practice, only a few patients can use it. If necessary, the battery containing the device is replaced „can” devices. The procedure itself is krotier than implantation, but still requires two to three days of hospitalization.

How often do you need to come in for check-ups?

The patient should remember to report for follow-up at the latestoThen on the next working day after the high-energy intervention (cardioversion, defibrillation) occurs. The occurrence of dwoch-three high-energy interventions within 24 hours is called an electrical storm. Such a condition requires calling an ambulance or immediately reporting to the hospital emergency department. Many devices signal with an audible tone the occurrence of events requiring control. Before discharge from the hospital, it is a good idea to ask the doctor whether the implanted device has such functions activated and how to behave in case of occurrence „alarm”.

What you can and cannot do with an implanted ICD?

Once the ICD has been implanted and the implantation wound has healed, the patient is generally not subject to any more restrictions than those thatore are due to the disease causing the implantation of the device. You can drive a carod, unless high-energy interventions occur frequently. ICD implantation does not constitute a roAlso a reason to limit in most casesoin working activity. Of course, someore occupations, such as pilot or professional driver, are not recommended for patients with ICDs.

– A patient with an implanted cardioverter-defibrillator can play amateur sports, but should inform the doctor so that the mohead properly programmed the device. Combat sports are not recommended. Using standard electronic and household devices, including telephoneoin comorkowych, is not subject to restrictions. If there are high electromagnetic field intensities in the work environment, it is necessary to consult a doctor in advance, and sometimes perform a detailedoexample measurementsow. Since someore medical procedures are not recommended in the patientow with an ICD, you should always inform the doctor recommending the procedure that you have an implanted device. Previously, it was completely contraindicated to perform in patientsow with ICD studies using magnetic resonance imaging. In modern devices this is possible, but is subject to certain limitations and requires appropriate reprogramming of the ICD.