STRA-MI-VT (STereotactic RadioAblation by Multimodal Imaging for Ventricular Tachycardia): rationale and design of an Italian experimental prospective study

Abstract

Background Ventricular tachycardia (VT) is a life-threatening condition, which usually implies the need of an implantable cardioverter defibrillator in combination with antiarrhythmic drugs and catheter ablation. Stereotactic body radiotherapy (SBRT) represents a common form of therapy in oncology, which has emerged as a well-tolerated and promising alternative option for the treatment of refractory VT in patients with structural heart disease. Objective In the STRA-MI-VT trial, we will investigate as primary endpoints safety and efficacy of SBRT for the treatment of recurrent VT in patients not eligible for catheter ablation. Secondary aim will be to evaluate SBRT effects on global mortality, changes in heart function, and in the quality of life during follow-up. Methods This is a spontaneous, prospective, experimental (phase Ib/II), open-label study (NCT04066517); 15 patients with structural heart disease and intractable VT will be enrolled within a 2-year period. Advanced multimodal cardiac imaging preceding chest CT-simulation will serve to elaborate the treatment plan on different linear accelerators with target and organs-at-risk definition. SBRT will consist in a single radioablation session of 25 Gy. Follow-up will last up to 12 months. Conclusions We test the hypothesis that SBRT reduces the VT burden in a safe and effective way, leading to an improvement in quality of life and survival. If the results will be favorable, radioablation will turn into a potential alternative option for selected patients with an indication to VT ablation, based on the opportunity to treat ventricular arrhythmogenic substrates in a convenient and less-invasive manner.

Stereotactic radioablation for the treatment of ventricular tachycardia: preliminary data and insights from the STRA-MI-VT phase Ib/II study

“…STRA-MI-VT is a spontaneous, prospective, single-arm, phase Ib/II single-center study. The design of the study has been detailed elsewhere [16]. Fifteen patients are expected to be enrolled and final results will be available after September 2022.…”

“…As previously described [16,19], cardiac CT was performed using a whole-heart-coverage CT scan (Revolution CT, GE Healthcare): a first CT scan was obtained at the angiographic phase as routinely performed for coronary CT angiography, and a second delayed series of breath-hold and ECG-gated images was acquired for the detection of myocardial DE (Fig. 2, upper panel).…”

Stereotactic Arrhythmia Radioablation Treatment of Ventricular Tachycardia: Current Technology and Evolving Indications

“…One of the major challenges in STAR was developing a reliable target delineation method which is crucial for the treatment success. Electroanatomic mapping (EAM) in combination with delayed enhancement cardiac computed tomography (CT) was mainly used to characterize the arrhythmia substrate and to define the target area [46,47]. Cardiac CT performed with intravenous contrast (or oral contrast if deemed necessary to demonstrate gastrointestinal tract for inferior wall targets) is useful to define all the cardiac structures, in particular, regions of scar based on myocardial wall thickness and myocardial delayed enhancement.…”

Stereotactic Radiotherapy in the Management of Ventricular Tachycardias

“…Several other prospective trials focused on efficacy and safety are ongoing, such as the German multicenter RAV-ENTA (NCT03867747) 26 and Italian STRA-MI-VT (NCT04066517). 27 Our recent experience with SBRT in patients with advanced heart failure, a higher proportion of nonischemic cardiomyopathy, and more catheter ablation sessions before SBRT also suggests that a significant percentage of patients have recurrences of VT after SBRT, and often need additional catheter ablations for frequent recurrences of VT. The effect of SBRT in a majority of cases appears to be delayed.…”