Stereotactic body radioablation therapy as an immediate and early term antiarrhythmic palliative therapeutic choice in patients with refractory ventricular tachycardia

Abstract

Background: Stereotactic body radioablation therapy (SBRT) has recently been introduced with the ability to provide ablative energy noninvasively to arrhythmogenic substrate while reducing damage to normal cardiac tissue nearby and minimizing patients' procedural risk. There is still debate regarding whether SBRT has a predominant effect in the early or late period after the procedure. We sought to assess the time course of SBRT's efficacy as well as the value of using a blanking period following a SBRT session.Methods: Eight patients (mean age 58 ±14 years) underwent eight SBRT sessions for refractory ventricular tachycardia (VT). SBRT was given using a linear accelerator device with a total dose of 25 Gy to the targeted area.Results: During a median follow-up of 8 months, all patients demonstrated VT recurrences, however, implantable cardioverter-defibrillator (ICD) therapies were significantly reduced with SBRT (8.46 to 0.83/per month, p=0.047; 18.50 to 3.29/per month, p=0.036, respectively). While analyzing the temporal SBRT outcomes, the two weeks to 3 months period demonstrated the most favorable outcomes. After 6 months, one patient was ICD therapy-free and the remaining patients demonstrated VT episodes. Conclusions: Our findings showed that the SBRT was associated with a marked reduction in the burden of VT and ICD interventions especially during first 3 months. Although SBRT doesn’t seem to succeed complete termination of VT in long-term period, our findings support the strategy that SBRT can be utilized for immediate antiarrhythmic palliation in critically ill patients with otherwise untreatable refractory VT and electrical storm.

Interim Report of a Japanese Phase II Trial for Cardiac Stereotactic Body Radiotherapy in Refractory Ventricular Tachycardia ― Focus on Target Determination ―

“…32 In one study of 8 patients, 1 case worsened at 12 months later than at baseline. 33 SBRT is also less effective for VT suppression in non-ICM compared with ICM. 34 Indications for cardiac SBRT should be carefully assessed taking into account the risk of VT-related death and radiation-induced late injury.…”