Patent ID: 7120491
Filing Date: 2006-10-10
Classification: A61N

Abstract:
1. An implantable cardiac stimulation device to provide therapy to a patient's heart, the device comprising: a sense amplifier to sense intrinsic signals from the patient's heart and to generate corresponding sense signals; a memory circuit to store interval thresholds to determine the type of antiarrhythmic therapy to be applied to the patient's heart for a range of heart rates defined by the interval thresholds; a control and timing circuit coupled to the sense amplifier and the memory circuit to generate control signals responsive to the sense signals and the interval thresholds, the control signals to define one of a plurality of antiarrhythmic therapies, wherein the therapy is selected in accordance with the relationship of the sensed heart rate and the interval thresholds; an interval threshold adjusting circuit to adjust the interval thresholds stored in the memory circuit in accordance with the response of the patient to the selected antiarrhythmic therapy; and a morphology discrimination circuit coupled to the control and timing circuit, at least one of the interval thresholds modified in accordance with a morphology detection applied to the intrinsic signals; wherein the interval thresholds define a very slow ventricular tachycardia zone, a slow ventricular tachycardia zone, and a fast ventricular tachycardia zone; wherein the at least one of the interval thresholds is an interval threshold VT wherein the QRS complex is compared with the stored template when a ventricular rate interval (VRI) is between 100% and 130% of the interval threshold VT