Radio frequency ablation

In the Radio frequency ablation it is a medical procedure in which defined areas of tissue are destroyed by high-frequency currents caused by the effects of heat.

The procedures are mainly used to destroy metastases in the liver and to treat atrial fibrillation. The high-frequency ablation can be carried out minimally invasively using a catheter and is therefore particularly gentle. It can be repeated if necessary in the event of recurrent problems.

What is radio frequency ablation?

The radio frequency ablation is synonymous as Radio frequency- or Thermal ablation designated. Using an applicator or catheter, electrodes are placed in the immediate vicinity of the tissue to be destroyed and heated by a high-frequency current of around 460 to 480 kilohertz.

Despite different, competing systems, the power consumption at the electrodes is usually around 200 watts. The effect of heat creates relatively sharply defined areas of destroyed tissue (heat necrosis), which can be further broken down by the body's own metabolism and, in the event of sclerotherapy in one of the auricles, loses its electrical conductivity and its electrical initiation potential. Radiofrequency ablation is usually performed using minimally invasive techniques.

This offers the advantage of repeatability in the case of unsatisfactory results or recurring problems. Fighting metastases in the liver removes significantly less valuable functional liver tissue than conventional surgical interventions.

Function, effect & goals

Radio frequency ablation is mainly used in two completely different areas of application. On the one hand, it concerns oncological applications, which mainly serve to combat metastases and, on the other hand, a cardiological treatment method of so-called atrial fibrillation.

In cancer medicine, thermal ablation is used less to destroy a primary tumor than to necrotize metastases if the primary tumor belongs to the class of tumors that can metastasize. There is extensive experience in the destruction of metastases in the liver and vertebral bodies - mostly as an adjunct therapy to chemotherapy and radiation therapy. However, there are no scientific studies that could prove the potential advantages of high-frequency ablation over open surgery.

It is generally assumed that the main advantage of the minimally invasive destruction of metastases located in the liver by thermal ablation causes less damage to the intact liver tissue than open surgical interventions. In surgical procedures it is inevitable that more functionally healthy liver tissue is removed than is the case with radiofrequency ablation. The goal of ablation in oncology is to keep the metastases from growing further and cause them to die. The use of high-frequency ablation in cardiology is less about the destruction of tissue and more about changing the electrophysiological properties of certain heart muscle cells so that they cannot transmit or generate any electrical stimuli to contract the atria.

Atrial fibrillation, which is relatively common in older people, is mostly due to the fact that myocardial cells in the left atrium near the confluence of the pulmonary veins transmit uncoordinated electrical signals from the pulmonary veins and cause the atria to contract very rapidly and with arrhythmia. They ignore the electrical impulses that the sinus node, the main clock in the right atrium, sends out. The goal of high-frequency ablation to combat atrial fibrillation is to make the heart muscle tissue around the junctions of the pulmonary veins electrically inactive.

This roughly corresponds to electrical insulation of the junctions of the pulmonary veins in the left atrium (pulmonary vein isolation). While the goal of thermal ablation in oncology is to destroy diseased tissue (metastases), the goals of high-frequency ablation for the treatment of atrial fibrillation are the sustained electrophysiological changes in basically healthy myocardial cells. The particular advantages of minimally invasive thermal ablation compared to surgical intervention are the repeatability of the ablation in the event of an unsatisfactory result or if recurrences occur.

The high-frequency ablation in atrial fibrillation is opposed to the so-called cryoablation, in which the ablation is achieved not through the effects of heat but rather through the effects of cold. The main advantage of cryoablation over thermal ablation is that the tissue in question can be pre-cooled during cryoablation. The electrophysiological effects can then be measured and checked. If the expected effect does not occur, the procedure can be canceled and the tissue is fully functional again after the temperature has been adjusted.

Risks, side effects & dangers

The direct risks associated with minimally invasive high-frequency ablation to combat metastases are estimated to be very low. They are below those of a conventional surgical procedure. The greatest "danger" is that the intended goals will not be achieved with the first treatment or that recurrences will occur.

In most cases, the thermal ablation can then be repeated without problems. The treatment of atrial fibrillation by radiofrequency ablation, for example in the left atrium, is also considered to be low-risk. However, there are higher technical risks because, for example, a planned electrical insulation of the pulmonary veins makes it necessary for a catheter to be advanced through an inguinal vein into the right atrium and then to pierce the septum between the two atria in order to enter the left atrium Near the junctions of the four pulmonary veins.

The main risks involved in this treatment are not so much the ablation being performed as the need to maneuver the cardiac catheter to the site in the left atrium. Possible complications can result from blood clots forming, which can cause thrombotic events, and from injury to the pericardium or esophagus. Heavy bleeding can also occur at the point of entry of the cardiac catheter into the inguinal vein. The above risk of injury is minimized if the procedure is performed by an experienced doctor.