Stereotactic Arrhythmia Radioablation as First-Line Treatment for Scar-Related Ventricular Tachycardia
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 发起方
- 入组人数
- 20
- 试验地点
- 1
研究概览
简要总结
Ventricular tachycardia (VT) is a dangerous fast heart rhythm originating from scarred areas of the heart muscle, often after a heart attack or in patients with cardiomyopathy. Patients with VT and structural heart disease typically receive an implantable cardioverter-defibrillator (ICD) to prevent sudden death. Despite the ICD, recurrent VT and ICD shocks remain common and are associated with poor quality of life. Current preventive therapies - antiarrhythmic medications and catheter radiofrequency ablation - have important limitations including side effects, incomplete effectiveness, and procedural risk.
Stereotactic Arrhythmia Radioablation (STAR) is a non-invasive treatment in which a single, precisely targeted dose of radiation is delivered to the scar tissue that gives rise to the abnormal heart rhythm. STAR has previously been studied in patients who have failed catheter ablation or are too high risk for that procedure, with promising results. However, STAR has not been formally evaluated as a first-line treatment.
This single-arm prospective feasibility study will enroll 20 adults with structural heart disease and sustained monomorphic VT. Each participant will receive a single 25 Gy fraction of stereotactic body radiotherapy (VMAT technique) targeted at the arrhythmogenic substrate identified by cardiac imaging, 12-lead ECG, and (where available) non-invasive electrocardiographic mapping or electroanatomical mapping. Participants will be followed at 6 weeks, 3, 6, 9, and 12 months to assess the primary efficacy outcomes (death, appropriate ICD shock, VT storm, and sustained VT below ICD detection rate after a 6-week blanking period) and safety outcomes (acute heart failure decompensation, drop in left ventricular ejection fraction, and STAR-specific toxicities such as pneumonitis, esophagitis, and pericarditis). The hypothesis is that STAR delivered as first-line therapy is safe and effective, with a comparable toxicity and efficacy profile to catheter radiofrequency ablation.
详细描述
Background:
Approximately 50,000 Canadians die suddenly each year. Ventricular tachycardia (VT) is the most common cause of sudden cardiac death, with the most common substrate being scar from prior myocardial infarction or non-ischemic cardiomyopathy. Implantable cardioverter-defibrillators (ICDs) reduce mortality but do not prevent recurrent VT; ICD shocks are painful, impair quality of life, and are independently associated with hospitalization and death.
Current strategies to prevent VT - antiarrhythmic drugs (primarily amiodarone) and catheter radiofrequency ablation (RFA) - both have significant limitations. Amiodarone use is limited by recurrence and adverse effects in up to 30% of patients. RFA is more effective than drug escalation but is limited by inability to access deep intramural, sub-epicardial, or papillary muscle substrate, hemodynamic instability during ablation, and large scar burden. Despite RFA, 20-50% of patients experience VT recurrence, with higher rates in non-ischemic etiology.
Stereotactic Arrhythmia Radioablation (STAR) - also called cardiac SBRT or cardiac radioablation - uses high-dose photon radiotherapy precisely delivered to the arrhythmogenic substrate. STAR is non-invasive and can target three-dimensional volumes anywhere in the heart, overcoming many of the access limitations of catheter-based ablation. Initial trials in patients ineligible for or refractory to catheter ablation have demonstrated safety and significant reductions in arrhythmia burden. A 2024 systematic review and meta-analysis of prospective trials (Miszczyk et al., Heart Rhythm 2024) reported VT burden reductions of >50%, >75%, and >95% in 90%, 80%, and 61% of evaluable patients respectively, with adverse events in fewer than 10%.
Southlake Regional Health Centre has previously completed an REB-approved feasibility study in 6 patients with refractory VT (acceptable toxicity, excellent outcome) and has subsequently treated 14 additional patients with recurrent VT despite prior catheter ablation under grant-supported studies. Earlier referral to ablation is associated with improved patient outcomes (Romero et al., JACC Clin Electrophysiol 2018), motivating a formal evaluation of STAR as a first-line treatment.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Treatment
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Age 18 years or older and able to provide informed consent
- •Structural heart disease with myocardial fibrosis identified on pre-procedural imaging, including imaging evidence of regional myocardial akinesis/thinning or documented scar on echocardiography, cardiac CT, or cardiac MRI
- •Sustained monomorphic ventricular tachycardia (symptomatic or requiring ICD shocks for termination) within the previous 6 months
排除标准
- •Reversible causes of VT (e.g., active ischemia, drug-induced, electrolyte abnormalities)
- •Acute coronary syndrome within 30 days, coronary revascularization (<90 days for bypass surgery, <30 days for percutaneous coronary intervention)
- •Patients previously treated with high-dose radiotherapy that precludes safe delivery of thoracic stereotactic radiotherapy (relative contraindication)
- •Patients requiring chest radiotherapy for an active cancer (relative contraindication)
- •VT targets cannot be identified or are not suitable for targeting with stereotactic radiotherapy (such as multiple foci of arrhythmia)
- •Patients who cannot tolerate the radiotherapy treatment position, or whose body habitus is not permissible by treatment bed requirements
- •Pregnant or breast-feeding women
- •Patients being considered for cardiac transplant who are deemed not eligible by their transplant team for STAR
研究者
Mouhannad Sadek
Principal Investigator
Southlake Health