Catheter Ablation for Atrial Fibrillation: A Modern Cardiology Procedure for Targeted Tissue Ablation

Catheter ablation is a specialized form of cardiac catheterization that uses electrical current to treat rapid arrhythmias.

For some types of heart rhythm disorders (tachycardias), catheter ablation is already the standard treatment today. While medications merely suppress the rapid heartbeat, catheter ablation can cure this condition.

Success rates are quite high; for example, for

• atrial flutter,
• AV nodal reentry tachycardias, or
• WPW syndrome

well over 90%.

Catheter ablation is performed based on a prior electrophysiological study. This examination of the heart serves to precisely determine the origin of the arrhythmia.

During this examination, the affected areas are identified. Treatment then follows via ablation. In this procedure, the affected tissue is altered by the application of energy, thereby interrupting the faulty signal transmission.

The classic method is RF ablation, a type of ablation that uses heat. Modern techniques such as pulsed-field ablation are also used.

After the procedure, the doctor checks whether the tachycardia (rapid heartbeat) can be triggered again. If not, the treatment was successful.

Cryoablation

In cryoablation, liquid gas is delivered through a metal electrode to the tip of the cardiac catheter. This causes the metal electrode to freeze solid to the muscle tissue. This prevents the cardiac catheter from slipping during ablation.

Temperatures of -80° C result in a cryoablation zone measuring a few millimeters in diameter.

Cryoablation is a painless procedure.

AV Node Ablation

Ablation of the AV node is also a commonly performed ablation procedure.

The AV node conducts atrial fibrillation only irregularly. This leads to significant arrhythmias in the ventricles. If the AV node is ablated, the irregular conduction of signals from the atria ceases.

However, the AV node is the heart’s “pacemaker.” Without the AV node, a pacemaker must take over this function—this is the disadvantage of AV node ablation.

The affected patient will be 100 percent dependent on the pacemaker in the future. Without its help, no more electrical impulses would be transmitted from the atria to the ventricles.

If the pacemaker were to fail, the patient would not die immediately. In that case, another natural pacemaker node within the ventricular muscle would take over. This node generates a replacement rhythm of about 20 to 40 beats per minute and allows the ventricles to continue “beating.”

Ablation of the AV node and implantation of a pacemaker usually lead to a significant improvement in quality of life.

The biggest drawback of AV node ablation is that the pacemaker must be replaced as soon as the batteries run out. This means that several surgeries will be necessary over the course of a patient’s life.

Catheter Ablation for Atrial Fibrillation

Catheter ablation for atrial fibrillation is a key treatment option for this condition. The goal is often what is known as pulmonary vein isolation.

In this procedure, the pulmonary veins that drain into the left atrium are electrically isolated. These areas are considered the source of many arrhythmias in patients with atrial fibrillation. 

Ablation for atrial fibrillation is used primarily for paroxysmal atrial fibrillation. In cases of persistent atrial fibrillation, treatment is more complex and often requires multiple procedures.

Following the cardiac catheterization procedure, a pressure bandage is applied, and heart activity is monitored via 

• ECG, 
• blood pressure measurement, or
• ultrasound

. Patients are typically discharged from the hospital after about 24 hours. Patients must initially remain on bed rest, especially if the catheter was inserted through the groin.

Nevertheless, the cardiac catheterization procedure carries some risks. The risk of complications is highest in patients with severe heart disease. The insertion of the cardiac catheter can lead to minor vascular injuries, which could be quite dangerous in the area of the heart. In rare cases, infections or blood clots may occur, which can cause a heart attack.

Today, both atrial arrhythmias and ventricular tachycardias are treated with catheter ablation. Success rates are strongly dependent on the patient’s overall health.

Catheter ablation is 90% successful in most people with narrowed blood vessels. In patients with pre-existing heart conditions, the success rate drops to below 50%.

Patients with ventricular tachycardia are also frequently implanted with a defibrillator (similar to a pacemaker).

Catheter ablation has been shown to provide better long-term control of symptoms compared to drug therapy.

The use of catheter ablation for atrial fibrillation is currently a rapidly growing field in cardiac research.

For this form of tachycardia, ablation using radiofrequency energy is not yet considered a standard treatment. To date, catheter ablation is only used when all other treatment options have been exhausted or the patient is suffering severely.

With atrial fibrillation, no clear source of the arrhythmia can be identified. This makes treatment using cardiac catheters all the more difficult. In most cases, ablation must be performed at many different sites to terminate the atrial fibrillation.

Thanks to studies, doctors now know that atrial fibrillation is very often caused by abnormalities in the four pulmonary veins. There, small strands of heart muscle connect the heart muscle tissue of the left atrium to the veins. Ablating these myocardial tongues is one of the treatment strategies for atrial fibrillation.

Professional societies such as the German Society of Cardiology, the European Society of Cardiology, the European Heart Rhythm Association, and the European Association for Cardio-Thoracic Surgery are continuously developing new guidelines.

Cardiologists also refer to this type of cardiac catheterization as “pulmonary vein isolation.” Pulmonary vein isolation is only an option for patients who suffer from paroxysmal atrial fibrillation.

The success rate for this cardiac catheterization procedure currently ranges between 50% and 70%. Sometimes a second treatment is necessary; in other cases, atrial fibrillation cannot be completely stopped. However, after catheter ablation, patients respond better to antiarrhythmic medications that had often become ineffective beforehand.

Ablation experts are typically cardiologists. A cardiologist specializes in the diagnosis and treatment of diseases of the cardiovascular system. After completing their medical degree, these heart specialists undergo residency training in internal medicine and cardiology.

This specialized training to become a certified cardiologist takes a total of 6 years.