Noninvasive cardiac radiation for ablation of ventricular tachycardia

The results of a new study show that noninvasive treatment with electrophysiology-guided cardiac radioablation substantially reduced the burden of ventricular tachycardia. Researchers from Washington University in St.

The results of a new study show that noninvasive treatment with electrophysiology-guided cardiac radioablation substantially reduced the burden of ventricular tachycardia. Researchers from Washington University in St. Louis combined noninvasive mapping (electrocardiographic imaging) and noninvasive ablation [stereotactic body radiation therapy (SBRT)] to treat patients with refractory ventricular tachycardia. SBRT is most commonly used to treat tumors, with high rates of tumor control and low rates of toxic effects. Patients were considered for noninvasive radioablation if they had had at least three episodes of implantable cardioverter–defibrillator-treated ventricular tachycardia in the previous 3 months, despite having received at least two antiarrhythmic medications and having undergone at least one catheter-ablation procedure (or having a contraindication to catheter ablation). Five patients with high-risk, refractory ventricular tachycardia underwent treatment in 2015. The average noninvasive ablation time was less than 15 minutes. While the patients had a combined history of more than 6,500 episodes of ventricular tachycardia in the 3 months before treatment, there were just 680 such episodes during a 6-week postablation "blanking period," when arrhythmias may occur due to postablation inflammation. Following that period, there were 4 episodes of ventricular tachycardia over the next 46 patient-months, for a 99.9% reduction from baseline. All five patients experienced a reduction in episodes of ventricular tachycardia. The researchers note that most of the patients were able to discontinue their antiarrhythmic medications several weeks after the treatment, and the antiarrhythmic effect continued throughout the first year.