Treatments & Therapies

Cryoablation – Treatment, Effects & Risks

Kryoablation

Cryoablation is the name of a technology with which certain heart muscle cells are changed by a cold stimulus in such a way that they can no longer generate or transmit an electrical stimulus. The technique represents an alternative to heat-based radiofrequency ablation and, like it, represents a minimally invasive method for ablating heart muscle cells in the right or left atrium to treat recurrent atrial fibrillation .

What is cryoablation?

Cryoablation is a cold technique used to treat cardiac arrhythmia, particularly recurrent atrial fibrillation. It represents an alternative to high-frequency ablation, in which certain cell areas in the right or left atrium are sclerosed with heat using a cardiac catheter.

It is also a minimally invasive procedure based on a heart catheter, which is advanced into the right atrium via suitable veins – usually starting from the groin. The left atrium is reached via a puncture of the atrial septum. The cell areas responsible for generating the arrhythmia are pre-cooled by the tip of the cryoablation catheter and then permanently electrically inactivated at temperatures of up to below minus 75 degrees Celsius. They can then neither generate nor transmit electrical impulses.

The cells are only changed in their electrophysical properties, i.e. they do not die off completely. The cryoablation is largely painless. Ablation using a cryoballoon catheter can be viewed as a variant of ablation using a cryoablation catheter. The technique is used to electrically isolate the pulmonary veins in the left atrium, which play an important role in recurrent atrial fibrillation by transmitting uncoordinated electrical impulses.

Function, effect & goals

In addition to the targeted obliteration of benign and malignant tumors, the main area of ​​application for cryoablation is the therapy of recurrent atrial fibrillation. The procedure can be performed as an alternative to high frequency or radio frequency ablation.

Scientific studies have shown that atrial fibrillation is mainly caused by muscle cells in the pulmonary veins that open into the left atrium. One of the main goals of cryoablation is therefore to electrically isolate the pulmonary veins from the left atrium so that the uncoordinated electrical signals from the atria can no longer be transmitted. The cryoablation catheter is advanced through a suitable vein into the right atrium, and after the atrial septum has been punctured, it can be placed in the left atrium near the confluence of the pulmonary veins.

First, the tissue to be ablated is pre-cooled and the doctor performing the procedure can electrophysiologically check whether the subsequent planned ablation would be effective and whether there are any unintended side effects or complications. Conversely, this means that the cryoablation can be stopped after the electrical check and the pre-cooled cells can recover and remain functional. The cryoablation therefore offers additional security because the effect can be checked before the actual irreversible ablation. This is particularly important when tissue near the AV node in the right atrium needs to be ablated.

The ablation itself consists of an extraordinary cold stimulus that is transmitted from the tip of the catheter to the surrounding heart muscle cells. The cells treated in this way irreversibly lose their ability to generate or transmit electrical impulses themselves. The cryoablation catheter can be used in the left or right atrium. As an alternative to the cryoablation catheter, the cryoballoon catheter was developed, which is used exclusively for the treatment of electrical pulmonary vein isolation. At the front end of the cryoballoon catheter, a tiny balloon can be filled with gaseous coolant.

The actual cold stimulus for sclerosing the adjacent tissue is caused by the evaporation of the coolant. The catheter is placed in such a way that the tiny balloon successively closes the entrances of the four pulmonary veins in the left atrium as completely as possible in order to achieve electrical isolation of the veins by inactivating the surrounding heart muscle cells. During the treatment it can be checked whether the isolation of the pulmonary veins was successful.

The cryoballoon procedure is slightly easier and safer to use than cryoablation catheter ablation, so the technique can also be used by clinics that do not have a differentiated cardiac center. The active principle of cryoablation has been used in open heart surgery for decades . Only the minimally invasive methods are relatively new.

Risks, side effects & dangers

One of the main problems after cryoablation for the treatment of atrial fibrillation is the recurrence of cardiac arrhythmia, which can usually be corrected by one or two re-ablations. But even then, the success rate is only 70 to 80 percent. A period of two years in which no more recurrent atrial fibrillation occurred is assumed to be successful.

After a cryoballoon treatment, it may be that only one or two of the four pulmonary veins are reconnected electrically, which can be taken into account in the eventual need for re-ablation. The risk that the ablation of heart muscle cells near the AV node itself will become inoperable is significantly lower with cryoablation than with high-frequency ablation, because the possibility of checking the function after pre-cooling the tissue area largely eliminates this risk.

A rare complication can be the formation of a blood clot (thrombus) on the catheter, which can detach and, in extreme cases, cause a stroke . To minimize this problem, the patient should be placed on anticoagulation prior to surgery. In very rare cases, infections can occur when the pulmonary veins are electrically isolated. When puncture of the atrial septum is required, bleeding at the puncture site has been reported in very rare cases.

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.