Severe ventricular arrhythmias: Radiotherapy may also help in the most serious cases.

Although it's not often discussed, ventricular tachycardia is one of the most dangerous heart rhythm disorders. Besides taking a significant toll on the health of those who suffer from it, in its most severe forms it is life-threatening. Thus, controlling a heart that tends to beat wildly often requires high-dose medications (with consequent possible side effects) or implantable defibrillators capable of delivering an electrical stimulus that corrects the heartbeat. All of this requires frequent hospitalizations, stress, and a reduced quality of life.

To best manage the situation, if medications or initial attempts at ablation (essentially "switching off" the site where the arrhythmia originates) aren't enough, it's still necessary to address the needs of patients, even those who are resistant to treatment. In this sense, stereotactic radiotherapy, targeting the target, could still be useful and carry less risk than a new ablation.

This possibility has been highlighted by the results of an analysis presented at the American Society for Radiation Oncology (ASTRO) conference and published in the International Journal of Radiation Oncology, Biology, Physics .

A possible alternative

Catheter ablation, the standard treatment for ventricular arrhythmias that don't respond to medications, requires anesthesia and the insertion of a small tube into the heart through a leg vein to destroy the abnormal cardiac tissue. While this treatment is effective, repeated procedures increase the risks associated with this technique. The study therefore suggests that radiation therapy could offer a comparable and potentially safer alternative to repeated catheter ablation for patients with severe heart rhythm abnormalities that cannot be controlled with medications.

In recent years, stereotactic radiation therapy for arrhythmias (also known as STAR) has emerged as a new, noninvasive alternative. By delivering precise beams of radiation to the scar tissue causing cardiac arrhythmia, it aims to achieve the same goal as ablation: restoring the heart to normal rhythm, without catheters or anesthesia.

The research presented at the conference, coordinated by Shannon Jang of Washington University in Saint Louis, paves the way for new approaches. "This is the first study to directly compare the results of cardiac radiotherapy with those of standard catheter ablation," the expert comments in a statement. "For patients who don't respond to traditional therapies and are at high risk of complications, noninvasive radiotherapy may represent a safer alternative to repeating an invasive catheter ablation procedure."

Research also in Italy

"STAR, or stereotactic radiotherapy for arrhythmias, represents a very promising approach for treating life-threatening ventricular arrhythmias," comments Giulio Molon , director of Cardiology at the IRCCS Sacro Cuore Don Calabria in Negrar. "It's non-invasive and therefore free of side effects, and can be performed in just a few minutes. It's highly precise and has already been established in the treatment of many cancers. The results of this study, in the field of cardiology, are very encouraging in this regard."

It should be noted that this intervention modality has been under evaluation for several years. The results of the first studies have already been published, and they are very promising. In this regard, it's enough to recall the ENCORE-VT study, previously published by the Washington University team, which demonstrated that cardiac radiotherapy was able to reduce ventricular tachycardia episodes and the use of antiarrhythmic drugs.

"At our center, we began this procedure in 2020, working with the European STOPSTORM consortium, funded by the European Union's Horizon 2020 research and innovation program. We are treating patients with implanted defibrillators and structural heart disease who have recurrent ventricular tachycardias," concludes Molon. "The preliminary results appear promising, and together with other current research, we will be able to define the role this strategy will play as an alternative to catheter ablation."