Patent ID: 6415179
Filing Date: 2002-07-02
Classification: A61N

Abstract:
A method for delivering defibrillation therapy to a patient's heart comprising the steps of:(a) positioning a defibrillation electrode in the right ventricle and a defibrillation electrode in the superior vena cava; (b) attaching a sensor in a low gradient region comprising the left ventriclar free wall region; (c) acquiring real time ventricular unipolar electrogram signals from said sensor and detecting a fibrillation episode in said patient's heart; (d) upon detecting a fibrillation episode during step (c), establishing a real time ventricular electrogram history based on unipolar electrogram signals acquired from said sensor for a first period of time and identifying the largest amplitude value of the established electrogram history, and establishing a reference amplitude value based as a percentage of said largest amplitude value; (e) monitoring said electrogram over a second period of time to detect for a first condition in which an amplitude parameter of the electrogram exceeds said reference amplitude value; (f) delivering a defibrillation shock to said heart fibrillation immediately upon an occurrence of said first condition during said second period of time, effective to terminate fibrillation; (g) continuing monitoring said electrogram to detect for a second condition in the event said second period of time elapses without the occurrence of said first condition, wherein the second condition occurs when the electrogram is monitored to be in downstroke; and (h) delivering a defibrillation shock to said heart fibrillation immediately upon the occurrence of said second condition, effective to terminate fibrillation.