SYSTEM FOR INDUCING TACHYCARDIA UTILIZING NEAR FIELD T-WAVE SENSING

摘要

A system and method are provided for inducing ventricular tachycardia in a patient to enable testing to determine the optimun parameters for antitachycardia stimulation. The implantable device provides for overdrive pacing of the heart for a short sequence, followed by delivery of a series of pulse pairs. Each pulse pair has a first stimulus pulse delivered at the same or similar overdrive rate, and an inducing pulse which is delivered in timed relation to the evoked T-wave, preferably during the falling edge portion of the T-wave. In this way, each cycle the inducing pulse is timed for efficaciously inducing techycardia. The timing of the inducing pulse is enhanced by near field sensing of the T-wave at about the location where the pulses are delivered, preferably using bipolar sensing and/or sense circuitry designed to recover the signal with an optimum time response. In one preferred embodiment, near field sensing is enabled by use of an FDC circuit. In another preferred embodiment, near field sensing is provided by a pacing lead having bipolar electrodes where the ring electrode is spaced less than 1 mm proximal to the tip electrode.