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。药物并不一定有效。昂贵的（每5年花费约4万美元）植入式除颤器在终止室性心动过速方面非常有效，但通常需要痛苦的电击。需要频繁使用除颤器治疗的患者可以考虑进行定位和消融。大约一半的VT患者心律失常起源于室间隔（分隔心脏两个底部的心肌）。心脏的这个区域很难从电的角度来绘制。一种名为Ensite 3000的新型测绘系统可以使用电极阵列从心脏腔内获取3300个虚拟电信号，而不必直接与心脏肌肉表面接触。我们对一个心室的Ensite系统进行了评估，发现它在识别异常电活动区域方面非常有效。使用Ensite同时从鼻中隔两侧进行测绘可能有助于绘制源自鼻中隔的室速。一旦发现异常区域，通常使用导管进行破坏，但其破坏心脏组织深处目标的能力有限。我们设计并开发了一种导管，它的尖端有一根针，可以造成更深的损伤。在这项研究中，我们将评估使用Ensite电极在患有室间隔室起源的慢性羊模型的双心室的绘图。Ensite地图将通过详细的接触（常规）地图进行验证。一旦确定，原型导管将用于摧毁VT的起源部位。本研究将使VT患者得到更有效的治疗，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.