A new application of computed tomography: stereotactic radiotherapy in the treatment of ventricular arrhythmias

: Stereotactic radiotherapy (STAR) represents a new and promising therapeutic option for patients with ventricular tachycardias refractory to conventional therapies; it allows the delivery of a high and highly shaped radiation dose on a three-dimensional target, inducing an anti-arrhythmic effect already in the first week post-treatment, mediated, in part, by the reprogramming of the electrical conduction of the substrate. The procedure's success depends on the precise definition of the target to be irradiated, made possible by integrating electrophysiological data and anatomical-structural information provided by non-invasive imaging methods. Among these, cardiac computed tomography, thanks to continuous technological progress, is configured as a valid alternative to magnetic resonance imaging. It distinguishes itself for faster execution times in patients who are often hemodynamically unstable and lower susceptibility to artefacts generated by implantable devices. Computed tomography allows the identification of relevant tissue characteristics of the arrhythmogenic substrate, such as wall thinning, adipose replacement, and, above all, myocardial fibrosis, which can be assessed through the analysis of the late iodine enhancement technique. Emerging technologies, such as photon counting scanners and advanced software for the three-dimensional visualization of tissue characteristics of electrophysiological interest, promise to further enhance the use of this imaging modality in the procedural workflow of STAR.