A novel means of cardiac catheter guidance for ablation therapy of ventricular tachycardia

Abstract

This work presents a system for identifying the site of origin of ventricular tachycardia (VT) and guiding a catheter to that site in order to deliver radio-frequency (RF) ablation therapy. Myocardial infarction (MI), also known as ischemic heart disease, is one of the most common pathophysiologic substrates for the development of ventricular tachycardia (VT). Implantable cardioverter defibrillators (ICDs) have been found to be successful in terminating VT but do not prevent the initiation of the arrhythmia. Alternatively, the radiofrequency (RF) ablation procedure has been recently used as a potentially curative therapy by delivering a high-frequency current at the arrhythmia site in order to disrupt the re-entrant circuit and to prevent the arrhythmia from occurring. However, RF ablation of VT presents a great challenge. The origin of the arrhythmia may be anywhere in the ventricles, and existing techniques used to locate the site require that patients be maintained in VT for 30 to 45 minutes, which leads to blood pressure collapse in 90% of the patients. Recently, we have developed a novel guidance system for the ablative treatment of VT. This system employs an Inverse Solution Guidance Algorithm (ISGA) based upon a single equivalent moving dipole (SEMD) model for the generation of body surface potentials and is able to localize both the arrhythmia site and the ablation catheter in real-time. With the proposed system VT need be induced and maintained for only a few seconds. This system has been shown in our tank experiment and in vivo animal studies to be highly accurate, low cost and reliable. An optimization analysis of the system is also included in this thesis for the purpose of further reducing the cost and surgical risk of the RF ablative therapy.