Cardiac Pacemakers, Inc.

University of Michigan

Lorenzo A DiCarlo

Jeffrey E Stahmann

Andrew P Kramer

James O Gilkerson

Rene H Wentkowski

Janice M Jenkins

Jaeho Kim

David L Perschbacher

Joseph M Bocek

Phillip Dewey Foshee, Jr

Harley G White

Anthony Harrington

Robert D Throne

Milton M Morris

Stephanie A Caswell

A method and system for managing refractory periods in a cardiac rhythm management device configured for biventricular or biatrial sensing. Refractory periods for each channel of the pacemaker are provided by interval timers that are triggered by sensed or paced events in order to prevent misinterpretation of sensing signals.

System for managing refractory periods in a cardiac rhythm management device with biventricular sensing

A method and system for generating a characterization of one beat of a patient's supraventricular rhythm (SVR) involves performing such characterization while the heart is being paced. During SVR characterization, various pacing parameters are modified and the patient's supraventricular rhythm is characterized while the pacing parameters are modified. The SVR characterization process is effective in single and multiple chamber pacing modes.

Method and system for characterizing supraventricular rhythm during cardiac pacing

System and method for managing refractory periods in a cardiac rhythm management device with biventricular sensing

A method and appartus for differentiating between ventricular tachycardia and ventricular fibrillation includes a pair of electrodes located on a single catheter which, in conjunction with an implantable cardioverter device, utilize two channel ventricular algorithms for ventricular tachycardia and ventricular fibrillation separation. Two closely spaced unipolar electrograms demonstrate similar morphology and consistency during rhythms with broad coherent activation (such as sinus rhythm and ventricular tachycardia). Conversely, for incoherent rhythms (ventricular fibrillation and polymorphic ventricular tachycardia), activation between the electrodes proved to be dissimilar and inconsistent. The cross-correlation of the two depolarizations measures similarity between electrogram morphology, and interquartile range measures consistency in a passage. The method and apparatus of the present invention is able to address the limitation of existing algorithms and provide accurate separation of ventricular fibrillation from other rhythms.

Method and apparatus for separation of ventricular tachycardia from

A pattern recognition system for use in an implantable cardioverter defibrillator that is capable of responding correctively to abnormal activity of the heart efficiently and specifically. The system of the present invention first establishes a template standard defining a median or other statistical measure of central tendency representing the point above which or below which actual sample values would be remarkable. Against the median are compared sampled values within a window having a pre-programmed length. For each cycle, a comparison is made between the template median and every value sampled within this pre-programmed window. Each cycle is then individually diagnosed such that if a selected value is above a particular pre-established threshold or below a particular pre-established threshold it will be classified as abnormal. A plurality of specific cycles must be classified abnormal in order for a final diagnosis to be made that the individual is experiencing arrhythmia. The system of the present invention is also capable of differentiating between types of abnormal and can classify the abnormal as being either ventricular tachycardia and ventricular fibrillation.

Method and apparatus for identifying and correctly responding to

A method and system are provided for monitoring electrocardiographic signals and detecting a pathological cardiac arrhythmia, such as ventricular tachycardia wherein the zero crossings of the first derivative of a reference template (i.e. reference waveform) are utilized to separate or partition both the template and each subsequent electrocardiographic signal being monitored into first and second sets of identifiable partitions. Each zero crossing is a boundary between adjacent partitions. Initially, the reference template is generated by acquiring a first set of wavefrom data representing a known good electrocardiographic signal. Identifiable partitions of the first set of data are then matched with corresponding identifiable partitions of the second set of data to obtain a performance measure signal. In one embodiment, the area beneath the derivative in each partition of the analyzed waveform is computed and compared (i.e. matched) to the corresponding area of the template. Preferably, a plurality of electrocardiographic signals are analyzed by utilizing the template and a plurality of performance measure signals are obtained. Finally, a therapy signal is provided as a function of the plurality of performance measure signals in the event of a pathologica cardiac arrhythmia, such as ventricular tachycardia.

Method and system for monitoring electrocardiographic signals and

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Ann Arbor, MI, United States of America

Lorenzo A DiCarlo