An Implantable Cardioverter-Defibrillator (ICD) is a device that protects the heart from major (life-threatening) ventricular arrhythmias such as ventricular fibrillation or ventricular tachycardia and helps to prevent sudden cardiac death. The ICD can automatically detect and recognize an arrhythmia and once evaluated, terminate it. The ICD is implanted, like a pacemaker, under the left clavicle, and electrodes are inserted into the heart through venous access.

The electrodes inserted into the heart muscle continuously sense the heart rhythm, and if a malignant arrhythmia is detected, the ICD automatically delivers therapy. This therapy can either be in the form of antitachycardia pacing (ATP) – a rapid sequence of stimulus pulses that can interrupt and terminate the arrhythmia – or, if this therapy is not effective, by delivering an electrical shock that terminates the arrhythmia.

CRT, or Cardiac Resynchronization Therapy, is a device used to treat dyssynchronous ventricular contraction (e.g., left bundle branch block). 

CRT is often referred to as a biventricular pacemaker because it provides synchronous ventricular pacing. The device usually has 3 electrodes (in some cases, only 2 electrodes in the ventricles): one electrode placed in the right atrium, the second in the right ventricle, and the third inserted through the coronary sinus to stimulate the left ventricle.

The ventricular electrodes are used for the synchronous stimulation of the right and left ventricles. 

CRT devices can be in the form of a pacemaker (CRT-P) or combined with a defibrillator function (CRT-D).

Catheter ablation is a relatively new method of treating heart rhythm disorders, allowing the destruction (i.e., ablation) of the abnormal tissue in the heart that is responsible for the disorder. Arrhythmias arise by two mechanisms. The first is called reentry, where a circular propagation of excitation occurs around a particular barrier in the heart. The second mechanism involves focal arrhythmias, where there is a pathological spread of activation from one location in the heart compartments.

Catheter ablation is performed in a non-surgical way (i.e., without the need for heart surgery), using special thin and flexible electrodes (catheters). During the procedure, a catheter is inserted through a vein or artery in the groin into the heart, and its tip is placed as close as possible to the site of the heart rhythm disturbance. An electrophysiological examination is then carried out. This examination consists of sensing electrical signals from different sites in the heart (monitoring the electrical activity in the heart and its propagation) and electrically stimulating different areas of the heart (monitoring the rate of propagation of the forced electrical activity). Stimulation of the heart is also used (in most cases of arrhythmias) to induce the corresponding heart rhythm disturbance from which the patient suffers. In some cases, various drugs may be administered during the arrhythmia or during the examination to facilitate the induction or termination of the arrhythmia. This helps confirm the diagnosis of the type of arrhythmia, which is a prerequisite for its removal by catheter ablation.

Once the type of arrhythmia has been identified, a special ablation catheter is inserted into the relevant part of the heart. This catheter has a steerable end, allowing easier searching for the site involved in the arrhythmia’s origin or maintenance. This can be the longest part of the procedure, as certain sites can be very difficult to access, and sometimes it is necessary to change the size of the catheter or try to reach the site from a different approach (e.g., from the neck instead of the groin). Once the site responsible for the arrhythmia is found, a special high-frequency electric current is passed into the catheter tip, which turns into heat and warms the heart tissue within a few millimetres around the tip. By “burning” a small area of tissue, the source of the rhythm disturbance is removed. Sometimes it is necessary to “burn” a slightly larger area of tissue to prevent the electrical excitation from circling. 

What is Percutaneous Coronary Intervention (“Stenting”)?

This procedure is used to dilate narrowed arteries or to open completely blocked vessels. The method is called percutaneous coronary angioplasty and stent implantation, simplified as “stenting.” During catheter insertion, the stretched or opened blood vessel is “reinforced” with a metal mesh stent. This stent remains in the vessel as a support apparatus to prevent it from collapsing again. Depending on the severity, one or more stents may be used. This procedure is performed in a similar way to coronary angiography. Angioplasty takes about 15 minutes in the mildest cases and 2 to 3 hours in the most severe ones. Hospitalization after uncomplicated angioplasty is typically 24 to 48 hours.

What is balloon angioplasty in peripheral vessels?

To access the vascular system, the doctor makes a small incision in the skin near the groin and inserts an introducer through which a balloon catheter is inserted into the femoral artery. The sheath of the introducer provides open and safe access for all the necessary instruments during the procedure. Once the introducer sheath is correctly positioned, the catheter is inserted into the vascular system. To pinpoint the exact location of the narrowing, the physician injects a contrast agent into the catheter. X-rays are then used to determine the location and extent of the narrowed or blocked part of the blood vessel. The doctor then inflates the balloon catheter. As it enlarges, the balloon presses plaque and other blocking material against the artery wall and opens the blood vessel to restore blood flow. Once the affected segment is successfully enlarged, the balloon is deflated and removed from the body. All other instruments are also removed, and the puncture site is carefully closed with a closure system.

What is Stent Implantation in Peripheral Vessels?

During angioplasty, the doctor inflates a special balloon inserted through a catheter to compress sclerotic plaques and masses against the artery wall, thereby expanding the inside of the vessel. This allows the restoration of nutrition and blood supply to the previously ischemic organ. When a stent is implanted, a small metallic grid – reinforcement – remains at the site of the narrowing, ensuring continuous blood flow. Over time, the stent becomes embedded in the vascular wall, a process known as epithelialization. During this period, the patient must have adjusted (reduced) platelet clotting and take medication for this purpose.

What is a Stent?

A stent is essentially a tube made of ultra-thin wires designed to reinforce the vessel wall from the inside. Peripheral stents are less often made of steel or chromium-cobalt alloy. Most commonly, the stent intended for the peripheral circulation is made of a nickel-titanium alloy (nitinol). Some stents are coated on the surface with a drug which, by gradual release from the stent, prevents the artery at the site from narrowing again.

Damage to blood vessels in prolonged diabetes causes a decrease in blood flow to the lower extremities, resulting in inadequate oxygen and nutrient supply to the tissues. This leads to slower wound healing and prolonged infection. Severely infected wounds never heal with inadequate blood supply.

What can a patient with diabetes do for the health of their feet? From the perspective of the underlying disease, good blood sugar control is crucial, and this must be maintained long-term. Therefore, strict adherence to the treatment and dietary measures recommended by the diabetologist is necessary.

It is also important that a patient with a non-healing wound on the leg is examined as soon as possible by a vascular specialist, such as an angiologist or vascular surgeon. 

Examination by a vascular specialist can reveal impaired blood supply to the lower limb, which is a significant factor in slowing wound healing in most patients with diabetes. However, in a large proportion of patients, this is a correctable problem.

In addition to the older surgical treatment, which involves creating a bypass (bridging) of a closed vessel, there is also the option of endovascular revascularization. This treatment is carried out under local anaesthesia and is therefore suitable for patients with other serious diseases that increase the risk of complications associated with surgical treatment. A balloon is introduced into the blocked blood vessel through a puncture in the groin. By inflating it, the narrowed blood vessel is widened, and if necessary, a metal reinforcement—a stent—is inserted into the blood vessel and left there permanently.