Catheter Ablation

Ablation in stead of life long medications?

Electrophysiological examination (EPU) is a special type of cardiac catheterization. It is generally used to accurately diagnose cardiac arrhythmias that are noticeable, for example, through symptoms such as palpitations or that have been detected by a previous ECG. The advantage of EPU is that the cardiac arrhythmias can be triggered, characterized, and terminated at the time of the procedure. If the cardiac arrhythmia is sufficiently confirmed, it can be treated with catheter ablation during the same procedure. Cardiac arrhythmias that require catheter ablation include supraventricular tachycardia or atrial fibrillation (= a variant of supraventricular tachycardia that manifests itself in a greatly accelerated heart rate, even over a longer period of time). Atrial fibrillation is a very common indication for catheter ablation, either as pulmonary vein isolation (rhythm control) or, less commonly, as pacemaker implantation followed by ablation of the AV node (rate control).

What is Rhythm-Control?

Rhythm control is a therapeutic strategy aimed at maintaining the natural sinus rhythm. In the case of acquired cardiac arrhythmias such as atrial fibrillation, treatment begins with lifestyle adjustments and the treatment of comorbidities such as high blood pressure and diabetes mellitus. Rhythm control may also include taking special medications and cardioversion (restoring normal heart rhythm in cases of cardiac arrhythmia).

Ablation treatment (our core competence) also belongs to the group of rhythm-preserving therapeutic measures.

Ablation instead of lifelong medications?

Recent studies ^[1] show that catheter ablation leads to better long-term results compared to lifelong medication. This is particularly true when taking the appropriate medication causes or can cause problems. Patients often suffer from taking the medication in a similar way to the actual symptoms of the disease that they are trying to prevent by taking the medication. Medication, as well as cardioversion, has only limited long-term effectiveness in treating atrial fibrillation and other arrhythmias. Thanks to the growing expertise of highly specialized physicians and constantly improving device technology (catheters, electrophysiological hardware and software), it is now possible to accurately measure and locate the electrically misdirected or missing impulses of individual cells.

The Ablation procedure

1. Pulmonary vein isolation - The first Step! 

Pulmonary vein isolation (PVI) has been an established and successful treatment for atrial fibrillation since the late 1990s. The key to the success of this method was the discovery that additional electrical impulses from the pulmonary veins can trigger atrial fibrillation. During ablation, these sources of interference are specifically ablated and electrically isolated. This makes it possible to prevent episodes of atrial fibrillation much more effectively than with medication alone. Today, the treatment is safe, effective, and gentle. However, it requires a great deal of experience, a well-coordinated examination team, and optimal organization to ensure the safety of our patients at all times.

A catheter is advanced through the groin to the heart. There, it enters the left atrium via a transseptal puncture. Here, the four pulmonary veins are cooled to -60 degrees Celsius at their openings using the balloon for 1 to 2 minutes each. The resulting “cold burn” leads to localized scarring of the tissue, preventing the disruptive electrical impulses from the pulmonary veins from spreading to the heart.

The first three months after ablation are referred to as the “blanking period.” During this time, recurrences may (but do not necessarily) occur. These may be brief, but additional medication or cardioversion may also be necessary. If atrial fibrillation recurs after the first three months (the blanking period), a second procedure is indicated. In this situation, 3D mapping and targeted ablation of the triggers are performed (see below).

2. 3D Mapping and Radiofrequency (RF) Ablatiuon - if the first one fails! 

If the first ablation (pulmonary vein isolation) was unsuccessful, 3D mapping is performed. Using a catheter that is advanced under sedation via the groin to the heart, an electrical map of the inside of the heart can be created “live,” i.e., while the heart is beating. Based on an exact three-dimensional anatomy and the visualization of the rhythm disturbance and the electrical conditions in the heart, the tissue responsible for the arrhythmia can be precisely located inside the heart. A catheter is then used to precisely target and ablate the tissue responsible for the cardiac arrhythmia using RF ablation (controlled ablation with radio frequency). In certain cases, this procedure can be repeated several times.

Images from inside the heart: Electroanatomical 3D mapping of the left atrium. Isolation of the pulmonary veins. The different colors show how vital the tissue is—purple is healthy, and red is diseased or scarred. The red dots are the points where RF ablation was performed. Circumscribed scars form there, which later prevent disruptive impulses from plunging the atrium into electrical chaos.

Ablation techniques

To isolate the pulmonary veins, the tissue surrounding the veins must be ablated. Various energy sources are available for this purpose:

• Cryothermia (Cold)
  

  In cryotherapy, a balloon is positioned at the end of the catheter and cooled to approximately –70 °C using nitrous oxide. Contact between the balloon and the tissue causes a cold burn, which turns into a small scar. This scar permanently blocks the faulty electrical signals. This technique has been used for over 20 years and is very well established.

• Radio frequency (RF)
  

  This involves creating a scar using selective electrical impulses. Using state-of-the-art 3D mapping, we create an electrical map of the atrium and identify precisely where there are still gaps in the insulation.

  This procedure is very accurate, but also complex, and we mainly use it for repeat procedures (recurrences).

• Pulsed Field Ablation (PFA)
  

  PFA is a new, non-thermal method. It involves delivering short, high-intensity electrical pulses that open the cell walls of the heart muscle cells (“electroporation”). The affected cells die in a targeted manner—other tissues such as the esophagus or nerves are spared.

  This technique is considered particularly gentle, safe, and forward-looking.

Advantages of catheter ablation

• Progression of atrial fibrillation. The progression of the disease is slowed down. Current studies show that early ablation yields the best long-term results. In paroxysmal atrial fibrillation in particular, it is important to perform ablation quickly in order to prevent scarring caused by the rapid pulse in the atrium.
• Fewer symptoms. Symptoms are improved. Attacks become less frequent and, when they do occur, the atrial fibrillation is significantly less noticeable.
• Discontinuation of medication. After ablation, it is often possible to reduce medication. This may be possible immediately, but sometimes certain medications are still necessary for a certain period of time. The use of blood thinners will then be discussed with your cardiologist depending on your risk factors.
• The heart recovers. The reduction in episodes and the associated rapid pulse allows the heart to recover. Recent studies show that heart failure can also regress after successful ablation.
• Repeat procedure possible. After ablation, it is possible to repeat the procedure. This may be necessary if the tissue recovers after the first ablation or if a new cardiac arrhythmia occurs. This is referred to as a redo procedure. This often serves to complete the ablation.

 What are the results of catheter ablation

The chances of success for catheter ablation in atrial fibrillation depend on many factors. How early is the atrial fibrillation treated aggressively, what has already been done previously?

• In paroxysmal atrial fibrillation, a success rate of over 95% freedom from atrial fibrillation after 12 months can be expected. Sometimes a second procedure is necessary to achieve this result. 
• In persistent atrial fibrillation, a success rate of between 70 and 90% can be expected.

 Who benefits the most from an ablation?

Most cardiac arrhythmias can now be treated with catheter ablation, which almost always yields significantly better long-term results than drug therapy. Catheter ablation is the method of choice for permanently eliminating distressing episodes of atrial fibrillation, atrial flutter, paroxysmal supraventricular arrhythmias, and some forms of ventricular tachycardia. Catheter ablation is a minimally invasive procedure, so patients can usually go home after an observation period of several hours. In certain situations, the ablation must be repeated. This is the case, for example, with more severe forms of atrial fibrillation. The more advanced the changes in the muscle of the left atrium, the more likely it is that multiple procedures will be necessary.

Patients who benefit most are those with:

• Severe symptoms
• Drug intolerance
• Complications from atrial fibrillation
• Newly occurring atrial fibrillation

The HeartTeam and the patient

The latest guidelines of the European Society of Cardiology recommend the cooperation of different specialists (cardiologist, electrophysiologist and cardiac surgeon) in the treatment of atrial fibrillation in order to achieve an optimal outcome for the patient.

This cooperation is summarized under the term "heart team".

Our "Heart-Team" will of course accompany you throughout your entire journey for the duration of your treatment!

References:

• Effect of Catheter Ablation vs Antiarrhythmic Drug Therapy on Mortality, Stroke, Bleeding, and Cardiac Arrest Among Patients With Atrial Fibrillation: The CABANA Randomized Clinical Trial – PubMed.gov 2. April 2019