Medtronic, Inc.

Weimin Sun

Eric J Panken

William J Combs

Gregory John Haubrich

Michael F Hess

John C Rueter

Garry L Dublin

Pamela A Abshire

Eric Olson

There is provided a system and method applicable for use with a dual chamber pacemaker for determining whether long atrial intervals are due to atrial undersensing or to sick sinus syndrome. The determination of undersensing is based upon an algorithm which statistically analyzes a long atrial interval in terms of the patient's prior atrial rate history, and compares a calculated statistical probability measure with an empirically determined undersense threshold factor. The pacemaker can respond to a determination of undersensing by correcting already collected diagnostic data, adjusting one or more pacemaker operating parameters, adjusting synchronous tracking and/or providing an annotated marker channel for indicating undersense events.

Medical device for automatic diagnosis of undersensing by timing

A microstrip RF telemetry antenna is formed on or within the exterior surface of an implantable medical device housing that is formed either of a conductive metal or of a non-conductive dielectric material. The microstrip antenna is formed of an electrically conductive radiator patch layer that is laminated upon an exterior facing side of a dielectric substrate layer of relatively constant thickness. A conductive ground plane layer is formed on the opposite side of the dielectric substrate layer to extend parallel to and at least coextensively with the radiator patch layer. The radiator patch layer is coupled to the transceiver circuitry within the implantable medical device housing by a feedthrough extending through the dielectric substrate layer, the ground plane layer and the implantable medical device housing side wall. If the implantable medical device housing is conductive it may form the ground plane layer over which the dielectric substrate layer and the radiator patch layer are formed through deposition or other techniques. If the implantable medical device housing is formed of a suitable non-conductive dielectric material, the ground plane layer is formed on an interior surface thereof and the radiator patch layer is formed on an exterior housing surface thereof, preferably by deposition techniques. The ground plane layer may be recessed to form a cavity backed ground plane that receives the dielectric layer and radiator patch layer within the cavity. The exterior surfaces of the radiator patch layer, the dielectric layer and any exposed surface of the ground plane layer may be electrically insulated by a radome layer.

Implantable medical device microstrip telemetry antenna

This is a method and apparatus for the automated discrimination of cardiac events of interest, including P-waves, R-waves, T-waves and specific arrhythmic sequences, in EGM signals for data storage in an implantable monitor or to control operations of an implantable cardiac stimulator through the use of Hidden Markov Modeling techniques and a reduced set of observations.

Method of selecting an operating mode for an implantable medical device

This is a method and apparatus for the automated discrimination of cardiac events of interest, including P-waves, R-waves, T-waves, and specific arrhythmic sequences, in EGM signals for data storage in an implantable monitor or to control operations of an implantable cardiac stimulator through the use of Hidden Markov Modeling techniques and a reduced set of observations. The number of computations and computation time during a heart cycle is reduced by timing the frames of A-EGM samples to the detection of A-SENSE events by the atrial sense amplifier. The A-EGM sample frame is defined in a window preceding and following each A-SENSE event. The A-EGM sample frames are wavelet transformed, and a number of selected W.T. coefficients for each sample frame are saved in a buffer. Each set of saved W.T. coefficients therefore represents either a P-wave or an intrinsic or paced far field R-wave (including fusion beats) unless noise continuously causes A-SENSE events to occur. When the V-SENSE event occurs, an R-trigger is generated, and each set of saved W.T. coefficients is subjected to the HMM algorithm for a determination as to whether the preceding (and any concurrent) A-SENSE events from which the saved W.T. coefficients were derived are P-waves or R-waves. In addition, when the V-SENSE occurs, the HMM algorithm determines stochastically whether or not the successive sets of saved W.T. coefficients represent P-P sequences, far field R-R sequences or P-R sequences or the like.

Method and apparatus for discriminating P and R waves

The present invention is a method and apparatus for processing a sensed atrial electrogram in conjunction with a sensed ventricular electrogram. The present invention permits accurate discrimination of atrial P-waves from far field ventricular events such as far field R-waves and avoids oversensing such far field ventricular events as atrial sense events and undersensing atrial events occurring within a fusion beat masked by a far field ventricular event in the atrial electrogram. Atrial channel trigger signals are generated in response to sensed P-waves and far field R-waves in the atrial electrogram, and ventricular trigger signals are generated in response to sensed R-waves in the ventricular electrogram. In response to each ventricular channel trigger signal, the sensed atrial electrogram signal is adaptively filtered for an adaptive filter time window only to remove the far field R-wave signal from the sensed atrial electrogram signal while avoiding adaptive filtering of the sensed atrial electrogram signal at other times. In response to each atrial channel trigger signal, the adaptively filtered, sensed atrial electrogram signal is subjected to morphological analysis in respect of a morphological model of a P-wave only during a morphology time window. In this manner, P-waves in the sensed atrial electrogram signal are detected and far field R-waves in the sensed atrial electrogram signal are not mistakenly detected as P-waves, while morphological analysis of the sensed atrial electrogram at other times is avoided.

Adaptive and morphological system for discriminating P-waves and R-waves

A method and apparatus for detecting tachycardia in a patient employs a digitally-sampled electrocardiographic signal input to a digital processor employing a Hidden Markov Modeling algorithm to eliminate confusion between far-field and near-field cardiac events to provide a more accurate measurement of cardiac rate for diagnosis and treatment.

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Plymouth, MN, United States of America

Weimin Sun