This is a single center, single arm, prospective and phase 1 clinical trial. Patients with refractory atrial fibrillation (AF) will receive single fraction stereotactic radiotherapy for pulmonary vein isolation. To minimize the potential risks associated with this innovative technique, the study has been designed in a stepwise dose escalation fashion under carefully observation by the investigators. The dose escalation is guided by 3+3 algorithm to ensure more patients will be spared dose limiting toxicities and more patients will be entered on the dose level than will be chosen as optimal dose of maximal effects. Low dosing levels with established safety profile will first be applied before administering higher dosing levels based on preclinical studies.~Safety is the primary endpoint of the study. Safety will be assessed by incidence and evaluation of any serious adverse evens using CTCAE V5.0 criteria associated with the procedure through 90 days (short-term) and 12 months (intermediate term). Efficacy will be evaluated by assessing atrial fibrillation recurrence (for paroxysmal AF) or AF burden (for persistent AF) after 90 days of blank period until 12 months post-treatment.
The study aims to investigate the short-term (3 months) and intermediate-term (12 months) safety and preliminary efficacy of stereotactic radiotherapy for pulmonary vein isolation to treat refractory atrial fibrillation.