Noncontact biventricular mapping and intramural ablation in a chronic ovine model of septal ventricular tachycardia

室性心动过速(VT)是一种起源于心脏底部的异常节律，是社区猝死的主要原因。药物治疗的效果并不可靠。昂贵的植入式除颤器(每5年花费约40,000美元)在终止VT方面非常有效，但经常需要痛苦的电击。需要频繁使用除颤器治疗的患者可考虑标测和消融。大约一半的室性心动过速患者的心律失常起源于间隔(分隔心脏底部的心肌)。从电学的角度来看，很难绘制心脏的这一区域。一种名为EnSite 3000系统的新型标测系统能够使用不必与心肌表面直接接触的电极阵列从心腔内采集3300个虚拟电信号。我们对心脏一个腔内的EnSite系统的评估发现，它在识别异常电活动区域方面非常好。使用ENSITE从间隔两侧同时标测起源于间隔的室速可能是有用的。一旦发现异常区域，通常使用导管进行破坏，但由于其破坏心脏组织深处目标的能力而受到限制。我们已经设计和开发了一种导管，它的尖端配备了一根针，可以产生更深的病变。在这项研究中，我们将评估在一个慢性绵羊模型中使用ENTITE电极在两个脑室的标测，其中室性心动过速起源于隔。EnSite映射将通过详细的联系人(常规)映射进行验证。一旦确定，原型导管将被用来摧毁室速的起源部位。这项研究应该能够更有效地治疗室性心动过速患者，提高他们的生活质量。

Ventricular tachycardia (VT), an abnormal rhythm originating from the bottom portion of the heart is the major cause of sudden death in the community. Medications are not reliably effective. Expensive (costing about $40,000 every 5 years) implanted defibrillators are very effective in terminating VT, but frequently require painful shocks. Patients who require frequent treatment from their defibrillators are considered for mapping and ablation. About half of the patients with VT have the arrhythmia originating from the septum (heart muscle separating the two bottom portions of the heart). This area of the heart is difficult to map from an electrical point of view. A new type of mapping system called the Ensite 3000 system enables acquisition of 3,300 virtual electrical signals from within a heart chamber using an electrode array that does not have to be in direct contact with the heart muscle surface. Our evaluation of the Ensite system in one chamber of the heart has found it to be very good in identifying areas of abnormal electrical activity. It is possible that simultaneous mapping from both sides of the septum using Ensite might be useful in mapping VT originating from the septum. Destruction of the abnormal area, once identified, is generally done using a catheter, but is limited by its ability to destroy targets deep in the heart tissue. We have designed and developed a catheter that is equipped with a needle at its tip that can create deeper lesions. In this study we will be evaluating mapping using the Ensite electrodes in both ventricles in a chronic sheep model with VT originating from the septum. The Ensite mapping will be validated with detailed contact (conventional) mapping. The prototype catheter will be used to destroy the site of origin of VT, once identified. This study should enable more effective treatment of patients with VT and improve their quality of life.