In a previous article we presented the causes, symptoms and ways of diagnosing patients with atrial fibrillation. In this article we will analyze the ways to treat atrial fibrillation with contemporary methods.

Read the first part of the article here > >

Maintain sinus pacing – why?

Maintaining sinus rhythm (normal heart rhythm) shall now be the first therapeutic approach for the majority of patients. Recent data in various studies show that sinus pacing, in addition to symptomatic relief for patients, also offers long-term benefits as it reduces cardiovascular mortality, strokes, myocardial infarctions, and hospitalizations for heart failure. These benefits appear to persist in elderly patients with significant comorbidities, while recent data show significant benefits even in patients with end-stage heart failure.

For a number of years the maintenance of sinus pacing in patients with atrial fibrillation was treated with drugs which on the one hand are not always effective and on the other hand have serious complications such as amiodarone. Catheter ablation has been the definitive drug-free treatment for a number of these arrhythmias for three decades.

Ablation initially began as a treatment for rhythmic supraventricular tachycardias and is now attempted in all types of supraventricular and ventricular arrhythmias.

We now have the ability to have advanced and modern 3D electroanatomical mapping systems where, apart from the geometric reconstruction of the cavity we are investigating, we can obtain information on the sinus potentials as an indication of normal or pathological myocardium (areas of scar - fibrosis), as well as the direction of its stimulus depolarization, both in the normal rhythm and during the arrhythmia.

Image 1: Geometric reconstruction of the heart's left atrium with a 3D electroanatomical mapping system. Purple areas represent atrial myocardium with normal potential (left atrium without scar).

Why is ablation indicated specifically for atrial fibrillation?

Atrial fibrillation first appears as an apparently innocent arrhythmia, and evolves into a disease with significant consequences. Despite receiving the correct anticoagulant treatment, according to current guidelines, the progression of the disease to a persistent and chronic form is accompanied by an increased frequency of strokes, myocardial infarctions, hospitalizations for arrhythmia, and increased cardiovascular mortality.

For this reason, today's position is an attempt to maintain the normal rhythm immediately after the diagnosis. A pharmacological treatment constitutes the usual practice, which however, apart from having significantly lower rates of normal rhythm maintenance, has also multiple side effects in long-term administration compared to ablation. Recent studies have managed to compare the progression rate to persistent and chronic Atrial Fibrillation and found that ablation by multiple mechanisms is significantly superior in maintaining sinus rhythm. For example, in a study with an average patient age of 59 years and a low risk for thromboembolic events, which compared the above two methods, it was shown that four times the number of patients developed persistent forms of atrial fibrillation in the drug group compared to ablation. In addition, an increased number of complications were observed, such as three strokes (when zero occurred in the ablation group), two cases of myocardial infarction and three hospitalizations. This means that, apart from the side effects directly related to the antiarrhythmics, the serious consequences of the progression of the disease, such as the above, should also be calculated, where, over time and with a larger number of patients, it may be proven that ablation prolongs survival, as well.

Is the possibility of recurrence a reason to prevent the operation?

In patients with heart failure and atrial fibrillation with severe or moderate left ventricular dysfunction who underwent ablation versus drug, atrial fibrillation with arrhythmogenic burden reduction alone prolonged survival (regardless of recurrence). Therefore, atrial fibrillation that may recur should not be considered as a failure of the intervention, that is quite often used as a criterion to prevent the procedure. A typical example of chronic disease is coronary artery disease, where patients who initially underwent angioplasty on one vessel may eventually need a second and third operation or even a coronary bypass.

Therefore, the bibliographic data of the last two years seem to prefer ablation of atrial fibrillation as the first form of treatment in patients who are deemed to require some form of treatment, given that, with the existing technology and acquired experience, it is a safe method with minimal significant complications.

What are the latest technological advances in treating arrhythmias and atrial fibrillation?

High frequency alternating current ablation has been used for 25 years in the treatment of atrial fibrillation with cryoablation as a second form of thermal ablation in the last 15 years.

Image 2: Pulmonary vein isolation and substrate modification (high-frequency alternating current ablation). Red areas represent dead atrial myocardium (scar areas).

In a recent study, the comparison of the two techniques showed no substantial differences in effectiveness and complications. However, in this study, the latest developments in thermal ablation, such as the integration of special algorithms for the duration of the damage, in order to be both effective and safe, as well as the existence of new catheters that allow the administration of very high energy, were not available at the time.

Recently, a new form of non-thermal energy, pulse energy, has been introduced. This form of energy has the advantage that its action is limited to the underlying tissue without permanent tissue damage of adjacent organs; thus it is safe, with no fear of a rare complication of an atrio-oesophageal fistula or a significant pulmonary vein stenosis. In a recent study comparing pulsed with thermal ablation gave comparable success results without the existence of significant complications. However, the current commercially available pulse ablation technology is not supported by an electroanatomical mapping system and is therefore limited only to pulmonary vein isolation, as happens with cryoablation.

In the near future, the technology that can be combined with an electroanatomical mapping system will be available, offering the possibility of choosing pulsed or thermal ablation, depending on the area, so that all clinical forms of atrial fibrillation can be treated with the same technology.

Image 3: Electrical isolation of the pulmonary veins using short-duration high-power energy (hybrid approach with 50/90W delivery).