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US 4,799,486 AGranted
Refractoriless atrial sensing in dual chamber pacemakers
AssigneeCardiac Pacemakers, Inc.
InventorRobert A. DuFault
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AssigneeCardiac Pacemakers, Inc.
InventorRobert A. DuFault
Estimating the term…
A method and apparatus for suppressing the ventricular component from an atrial sensing lead used with a dual chamber cardiac pacer, thus obviating the need for an atrial sense refractory period to prevent oversensing of the ventricular interference. The invention utilizes an adaptive filter embodying the Widrow-Hoff least mean square (LMS) algorithm which is connected to receive signals from an endocardial lead having a bipolar ventricular electrode and a unipolar atrial electrode. The bipolar electrodes disposed in the ventricle are connected as the "input" X.sub.k signal to the LMS adaptive filter while the unipolar atrial electrode output is connected as the "desired" or reference signal d.sub.k. In accordance with the LMS algorithm, the "error" signal is fed back and used to adjust the tap weights of the adaptive linear filter until the output thereof closely approximates the "desired" signal and then the "error" signal becomes a good approximation of the atrial signal alone, without the ventricular depolarization signal.
In a dual chamber cardiac pacer of the type having first electrode means disposed in the ventricle of the heart for detecting ventricular depolarization signals and second electrode means disposed in the atrium of the heart for primarily detecting atrial depolarization signals, atrial sensing means responsive to the signals on said second electrode means for suppressing those signals on said second electrode means due to said ventricular depolarizing signals comprising:
A method of operating a dual chamber pacemaker of the type including ventricular pacing means, ventricular sensing means and atrial sensing means such that natural or artificial electrical activity originating in the ventricle is not oversensed by said atrial sensing means, comprising the steps of:
Dependencies are inferred from the claim text.