临床前研究和病例报告表明立体定向放射治疗在一些恶性肿瘤的治疗中很有效，可能对难治性室性心动过速（VT）有效。 在一个单中心病例系列研究中，5例患有先前射频消融失败的结构性心脏病患者（或者不是消融候选者）以及持续性VT，尽管有两种或更多种抗心律失常药物，但立体定向放射治疗可以减少过多的VT负荷 99％，一般耐受性良好。 鉴于患者人群室性心律失常的减少程度有限，而其他治疗方案有限，立体定向放射治疗是一种潜在的有吸引力的治疗方法，但在更大规模的研究中需要额外的有效性和安全性评估。
BACKGROUND Recent advances have enabled noninvasive mapping of cardiac arrhythmias with electrocardiographic imaging and noninvasive delivery of precise ablative radiation with stereotactic body radiation therapy (SBRT). We combined these techniques to perform catheter-free, electrophysiology-guided, noninvasive cardiac radioablation for ventricular tachycardia.
METHODS We targeted arrhythmogenic scar regions by combining anatomical imaging with noninvasive electrocardiographic imaging during ventricular tachycardia that was induced by means of an implantable cardioverter-defibrillator (ICD). SBRT simulation, planning, and treatments were performed with the use of standard techniques. Patients were treated with a single fraction of 25 Gy while awake. Efficacy was assessed by counting episodes of ventricular tachycardia, as recorded by ICDs. Safety was assessed by means ofserial cardiac and thoracic imaging.
RESULTS From April through November 2015, five patients with high-risk, refractory ventricular tachycardia underwent treatment. The mean noninvasive ablation time was 14 minutes (range, 11 to 18). During the 3 months before treatment, the patients had a combined history of 6577 episodes of ventricular tachycardia. During a 6-week postablation "blanking period" (when arrhythmias may occur owing to postablation inflammation), there were 680 episodes of ventricular tachycardia. After the 6-week blanking period, there were 4 episodes of ventricular tachycardia over the next 46 patient-months, for a reduction from baseline of 99.9%. A reduction in episodes of ventricular tachycardia occurred in all five patients. The mean left ventricular ejection fraction did not decrease with treatment. At 3 months, adjacent lung showed opacities consistent with mild inflammatory changes, which had resolved by 1 year.
CONCLUSIONS In five patients with refractory ventricular tachycardia, noninvasive treatment with electrophysiology-guided cardiac radioablation markedly reduced the burden of ventricular tachycardia. (Funded by Barnes-Jewish Hospital Foundation and others.).
