External ablation of ischemic ventricular tachycardia in an animal infarct model using a scanned proton beam

心肌梗死后缺血性心肌病患者发生危及生命的室性心律失常的风险很高。全世界每年有超过400万例心源性猝死，其中大多数是由室性心律失常引起的。除了植入植入式心律转复/除颤器外，近年来室性心动过速（VT）的导管消融也被越来越多地采用。使用射频电流消融室性心肌的致心律失常区。虽然在日常临床实践中已经建立了这种方法，但目前在不超过50%的病例中，这种方法可以长期消除VT。这种有限成功的一个原因在于难以在整个壁内范围内均匀化致心律失常性梗死边界区。由Packer教授和其他人组成的小组的初步工作表明，使用放射治疗方法进行心肌消融是可能的。由于其物理特性，质子束特别适合于靶向能量应用，同时保护周围器官处于危险之中。因此质子治疗越来越多地用于放射肿瘤学。在这个项目中，我们将在体内研究使用质子束治疗无导管消融心肌梗死后室性心动过速。在建立猪心肌梗死后VT模型的治疗计划方法后，应用质子束治疗。然后通过电生理研究和完整动物的多模态成像分析治疗效果，然后进行组织学检查。无导管消融有可能带来室性心律失常临床治疗的范式转变。

Patients with ischemic cardiomyopathy after myocardial infarction are at high risk for developing life-threatening ventricular arrhythmias. Every year there are over 4 million cases of sudden cardiac death worldwide, most of which are caused by ventricular arrhythmias. In addition to implantation of implantable cardioverters/defibrillators, catheter ablation of ventricular tachycardia (VT) has increasingly been adopted in recent years. Arrhythmogenic areas in the ventricular myocardium are ablated using radio-frequency current. Although being established in everyday clinical practice, this method currently results in long term freedom from VT in no more than 50% of cases. One reason for this limited success lies in the difficulty of homogenizing the arrhythmogenic infarct border zone in its entire intramural extent.Preliminary work by the group of Prof. Packer and others has shown that myocardial ablation is possible using radiotherapeutic approaches. Due to their physical properties, proton beams are particularly suitable for targeted energy application while protecting surrounding organs at risk. Proton therapy is therefore increasingly used in radio-oncology. In this project, we will investigate catheter-free ablation of ventricular tachycardias after myocardial infarction using proton beam therapy in vivo. After developing methods for treatment planning in an established swine model for VT after myocardial infarction, proton beam therapy is applied. Treatment effects are then analyzed by electrophysiological studies and multi-modal imaging in the intact animal before the lesions are examined histologically. Catheter-free ablation has the potential to bring about a paradigm shift in the clinical treatment of ventricular arrhythmia.