Magnetic resonance guided stereotactic radioablation for septal ventricular tachycardias

Abstract Background Stereotactic Arrhythmia Radioablation (STAR) was introduced to treat Ventricular Tachycardia (VT) refractory to catheter ablation. Poor data are now available in the septal VT substrate setting, representing a challenge when using conventional techniques. Objectives To evaluate the arrhythmic burden in patients with septal VT treated with Magnetic Resonance imaging guided STAR (MRgSTAR). Methods We enrolled consecutive patients with septal VT substrate. The therapy target was achieved by combining anatomical/functional and electrophysiological information. Patients were treated with a single fraction of 25Gy adopting MRgSTAR. All patients were clinically followed-up, and all implantable cardiac devices were remotely monitored. The efficacy outcome included recurrences of any sustained VT beyond the 6-week blanking period after MRgSTAR. The safety outcome was the incidence of adverse events and Atrioventricular Block (AVB). Results We included 16 patients with septal substrate VT [median age:68.5yrs (IQR:63.75–77yrs); 81.3% male]. Clinical presentation was an electrical storm in 75% of patients. No complications occurred after MRgSTAR, and ten (62.5%) patients were discharged on the same day of treatment. During a mean follow-up of 13±7 months, the efficacy outcome occurred in five (31.3%) cases (Figure 1). A significative reduction of Implantable Cardioverter Defibrillator (ICD) therapy (25.1 before MRgSTAR vs 1.9 after MRgSTAR, p-value:<0.001) was observed (Figure 2). Left ventricular ejection fraction increased significantly after treatment [38%(IQR:33.5-46.5%) before MRgSTAR vs 44.4%(IQR:35–47%) after MRgSTAR; p-value:0.04]. No adverse effects were observed in the ICD and lead system; in the seven patients with preserved atrioventricular conduction, no AVB was reported. Conclusion MRgSTAR represents a safe and effective strategy for treating septal VT.Follow-up of pts treated with MRgSTAR Number of ICD therapy during follow-up.