Successful cold treatment (cryoablation) of atrial fibrillation

Treatment of atrial fibrillation (AF) with cold is a novel technique that allows electrical disconnection of the main veins, which are the main cause of the condition. Moncloa University Hospital is the leader in Spain in this treatment.

What does treatment of atrial fibrillation with cold consist of?

The treatment of atrial fibrillation with cold consists of addressing the problem at its origin which, contrary to what may be thought, is not the atrium but the pulmonary veins. For some years now, in order to definitively treat this type of arrhythmia, it has been decided to electrically disconnect the pulmonary veins of the left atrium in a complete circumferential manner. Various forms of energy have been used for this purpose, such as radiofrequency, laser or, in our case, cold.

What is achieved with cold in the treatment of AF?

To disconnect the pulmonary veins from the left atrium, a double-chamber balloon is used, over which nitrous oxide is recirculated for 240 seconds at an average temperature of -50ºC. Unlike radiofrequency heat, the lesion produced by cold does not produce proliferation of fibroblasts, which constitute the cellular basis for the formation of cartilaginous tissue, which can be responsible for producing stenosis in the treated veins. In this way we minimize the appearance of potential problems and complications.

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Results of atrial fibrillation treatment with cold

We have been applying cold in the treatment of atrial fibrillation since 2008, when we introduced the technique in Spain and published the first cases in the “Revista Española de Cardiología” a year later, with very good results.

Last May 2016, they have published in the “Journal of Atrial Fibrillation” the longest term follow-up of patients treated with this technique so far published in patients with paroxysmal AF. In these more than seven years we have achieved a success rate of 89.1% after a first intervention, and 11% clinical recurrences, which, after a second intervention, remain in sinus rhythm all patients, without medication, antiarrhythmic drugs or anticoagulation.

Indications for cold treatment of atrial fibrillation

The successful outcome of this technique is due in part to the selection of the patients, in addition to the performance of the intervention. As with many other diseases, such as cancer, the earlier it is diagnosed and treatment begins, the greater the chances of success. This is because the longer the patient is in AF, the more likely they are to stay in AF, as atrial fibrillation generates more atrial fibrillation.

Stages of atrial fibrillation

There are three stages of atrial fibrillation:

  • The first, known as the paroxysmal stage; this is the one where episodes do not last more than 24 hours and disappear spontaneously. In these cases we have achieved a cure rate of over 90%.
  • The second, persistent atrial fibrillation of short duration, has episodes lasting 7 to 10 days and responds well to drug administration. The cure rate with cold intervention is between 60 and 80%.
  • The third is long-standing persistent fibrillation, in which the patient has been suffering episodes for a longer period of time and has already undergone atrial remodeling. In this case, and this is the great challenge for the future, we are talking about a 60% cure rate in the first intervention, 72% after the second and 78% if supported by drugs.
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What is atrial remodeling?

With the perpetuation of the arrhythmia, a process of readaptation of the heart begins, known as remodeling. This is an anatomical, electrical, biochemical and hormonal process that leads to dilatation of the atrium and subsequent fibrosis that can cause the arrhythmia to be generated or perpetuated without the participation of the pulmonary veins. Cure is more difficult in such cases; even if we electrically disconnect the veins, the success rate is lower because the diseased atrium itself can produce AF on its own.

Symptoms of atrial fibrillation

People who perceive the arrhythmia usually go to the Cardiology specialist in alarm, and this is the one who starts the process. The problem we encounter is that there are many people affected who do not notice the symptoms of the arrhythmia, so it is more difficult to detect it (to the point that many of them arrive at the hospital after suffering heart failure or even a stroke, a problem directly related to atrial fibrillation).

My advice is that if a person feels more tired than usual, sees that he/she cannot stand the level of physical exercise and even feels apathetic or has lost enthusiasm, regardless of whether he/she feels palpitations or not, he/she should have a check-up to rule out AF.

What is atrial fibrillation?

Atrial fibrillation is the most common arrhythmia in humans over 50 years of age. It is the most common arrhythmia in any form of heart disease and increases the risk of stroke by a factor of 5 in patients who suffer from it.

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The origin of AF is in the pulmonary veins, where a continuous bombardment of electrical impulses (more than 600) is generated, reaching the atrium and causing it to fail, giving way to an arrhythmia in the form of rapid and irregular fluttering or twitching.

The mechanical efficiency of the heart is seriously altered, and a healthy person pumping 7 liters of blood per minute, on entering AF, would drop to about 4 liters, with the consequent loss of functional capacity: fatigue, maladaptation to physical exercise… In addition, AF slows blood circulation, favoring blood clotting and the risk of thrombus and stroke.