Photo Credit: Tingting Ji
The following is a summary of “Mechanistic insights and knowledge gaps in the effects of radiation therapy on cardiac arrhythmias,” published in the September 2024 issue of Oncology by Balaji et al.
Stereotactic body radiation therapy (SBRT) has emerged as a groundbreaking treatment modality for refractory ventricular arrhythmias (VA), offering a significant reduction in VA burden—exceeding 85%—as demonstrated in Phase I/II clinical trials. This innovative approach is particularly notable for its ability to deliver effective treatment in an outpatient setting, where patients receive SBRT in a fraction over 15 to 30 minutes without sedation, anesthesia, or surgical intervention.
The short-term safety profile of SBRT has been favorable, making it a clinically relevant option for patients with limited alternatives. Despite these promising outcomes, the precise mechanisms by which SBRT exerts its anti-arrhythmic effects remain poorly understood. Current clinical dosing protocols for SBRT are based on preclinical studies designed to induce transmural fibrosis in the atria, a process that takes time to develop. Intriguingly, the beneficial effects of SBRT in patients with VA appear much sooner than the typical timeline for fibrosis formation, suggesting alternative mechanisms at play.
This review seeks to explore the possible ways radiation therapy modifies the electrophysiological properties of cardiac myocytes and alters myocardial conduction, contributing to its anti-arrhythmic effects. By elucidating these underlying mechanisms, the review aims to bridge the gap between clinical observations and scientific understanding, guiding future research in this promising therapeutic area.
Source: sciencedirect.com/science/article/abs/pii/S0360301624033169
