Heart ablation is the term used by cardiac specialists for the treatment of cardiac arrhythmias in which they deliberately obliterate pathological areas of the heart muscle tissue. Catheter ablation can permanently repair certain forms of cardiac arrhythmias. Beginnings of this treatment method exist since the eighties. Since then, technology has made tremendous progress. Today, numerous cardiology departments perform the procedure.
How does a catheter ablation work?
Understanding the principle of catheter ablation requires some basic knowledge of how the heart works: the heart consists of four heart cavities, two atria, and two main chambers. The beating of the heart is generated by electrical impulses that arise at a specific location in the right atrium. From this so-called sinus node, the electrical impulses spread over the atria and the atrioventricular node (AV node) on the heart chambers and cause the contraction of the heart muscle (conduction system see also graph).
Insert the catheter into the right atrium for ablation. The conduction system is shown in yellow
If there are additional faulty pathways or sites in the myocardial tissue that trigger further excitement, there will be episodic or persistent irregular heartbeat. This can be treated by the so-called catheter ablation. Depending on the cause of the disease, the doctors either devour the starting point of the additional heartbeats or the abnormal pathways.
When will a catheter ablation be used?
For most forms of cardiac arrhythmia, the doctor will first try to treat them with medication. If this therapy fails, catheter ablation can permanently rid the patient of his symptoms in certain types of arrhythmia:
In Wolff-Parkinson-White syndrome (WPW syndrome), there is a congenital pathway between the atria and the ventricles as a short circuit. About the short-circuit connection, the excitement reach the chambers prematurely. It comes to the attacking tachycardia. After catheter ablation, when the expert obliterates the extra pathway, cardiac arrhythmia has disappeared in over 95 percent of cases.
In AV node reentry tachycardia, the electrical impulses circulate in the AV node. This causes tachycardia. Catheter ablation is the treatment of choice for this common cardiac arrhythmia and is successful in more than 95 percent of cases.
In atrial tachycardia (“atrial tachycardia”), the electrical impulses do not emanate from the sinus node but from other locations in the right atrium. The chances of a successful catheter ablation are slightly lower in atrial tachycardia than in WPW syndrome and AV node reentry tachycardia.
In typical atrial flutter, there is also a circular excitement in the right atrium. As the cardiac arrhythmia can be permanently cured by the catheter ablation in 95 percent of cases, it is clearly superior to the drug therapy.
ECG curve for atrial fibrillation
Atrial fibrillation can be caused by electrical impulses from the pulmonary veins. When atrial fibrillation causes discomfort such as shortness of breath or heart failure, doctors use catheter ablation to electrically isolate the pulmonary veins. As a result, the interfering impulses should no longer reach the forecourts. The procedure lasts several hours. So far, he has been successful in seizure-related atrial fibrillation in about 70 percent of cases. For chronic atrial fibrillation, the success rate is just over 50 percent. Therefore, catheter ablation is only used when medications can not normalize the heart rhythm. Often, the patient must continue to take medication after ablation. In some cases, the catheter ablation needs to be repeated.
Although isolation of the pulmonary veins is not possible, there is still the possibility of AV node ablation. By sclerosing the AV node, the atria and chambers of the heart are completely separated electrically. The patient then needs a pacemaker. Therefore, AV node ablation is only an emergency solution.
How does a catheter ablation work?
Catheter ablation is usually performed as part of an electrophysiological examination (EPU) in the hospital. The standard procedure is radiofrequency ablation. Their principle is that the catheter tip delivers heat to the tissue with pinpoint accuracy. Other ablation procedures work with cold (cryoablation).
The inpatient admission usually takes place the day before the procedure so that the medical history can be recorded, the reconnaissance interview conducted and necessary preliminary examinations can be made.
Catheter ablation is performed like a cardiac catheter or EPU under local anesthesia. The patient is conscious. If necessary, the doctor administers painkillers and sedatives. First, the doctor examines exactly the cardiac arrhythmias and their place of origin in the EPU. Then he sets in the heart tissue on the ablation catheter targeted small scars of a few millimeters, to prevent the emergence or transmission of cardiac arrhythmia. After the sclerotherapy, if necessary, the doctor tests whether the cardiac arrhythmia can still be triggered by electrical impulses.
The duration of the procedure is very variable and can hardly be predicted. It can take two to six hours or, in some cases, even longer. The procedure after the procedure is similar to the follow-up treatment with the EPU: The doctor removes the catheters from the heart. In order to prevent rebleeding, he supplies the puncture site with a pressure dressing, which should remain there for 6 to 12 hours. During this time, the patient must observe strict bed rest so that the dressing does not slip. Mostly he can go back to work after a few days.
What are the risks and side effects of catheter ablation?
In most cases, the procedure is without complications. The complications that can occur with catheter ablation are essentially the same as those of the EPU. The doctor discusses it with the patient in a consultation before the examination.