Medtronic, Inc.

Medtronics, Inc.

John C Rueter

Luc Roland Mongeon

Todd Jon Sheldon

Yong Kyun Cho

John E Burnes

David A Igel

Jodi Zilinski

Harry Stone

Harold Toby Markowitz

Christopher M Manrodt

H Toby Markowitz

Karen J Kleckner

Douglas A Hettrick

Thomas J Mullen

Paul A Belk

William J Combs

Catherine R Condie

Michael F Hess

John Charles Stroebel

James W Busacker

Edwin G Duffin

Trent M Fischer

Daniel Robert Kaiser

Ren Zhou

Weimin Sun

Harold E Stone

Bruce L Wilkoff

Eric Olson

Gary J Syring

David E Igel

Jody Zlinski

The present invention provides a technique for verifying pacing capture of a ventricular chamber, particularly to ensure desired delivery of a ventricular pacing regime (e.g., 'CRT'). The invention also provides ventricular capture management by delivering a single ventricular pacing stimulus and checking inter-ventricular conduction during a temporal window to determine if the stimulus captured. If a loss-of-capture LOC) signal results from the capture management testing, then the applied pacing pulses are modified and the conduction test repeated. If LOC, an alert message can issue. Other aspects include: use of a trend of A-RV/LV and LV-RV timing intervals to monitor changes in the patient's heart conduction properties; bi-ventricular verification test and search&#x2014;while still pacing BiV by detecting latent sense; single-V pacing threshold search, use of timing of sense in other V chamber to establish capture and LOC windows; (iv) use of a premature V pace rather than short AV interval if VV cannot be discriminated from AV; (v) option to run a threshold search only if the Bi-ventricular verification test fails.

Bi-ventricular ventricular capture management in cardiac resynchroniziation therapy delivery devices

Methods and devices for determining optimal Atrial to Ventricular (AV) pacing intervals and Ventricular to Ventricular (VV) delay intervals in order to optimize cardiac output. Impedance, preferably sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change.

Algorithm for the automatic determination of optimal AV and VV intervals

An implantable medical device and associated method provide atrial pacing and measure an atrial ventricular (AV) delay. An autonomic function index is computed using the AV delay. The autonomic function index may be compiled in a medical report. In some embodiments, the autonomic function index is used to adjust atrial pacing control parameters.

Algorithm to modulate atrial-ventricular delay and rate response based on autonomic function

An implantable cardiac stimulation system and method having continuous capture management capabilities are provided. Continuous capture management is realized by continuously monitoring for secondary effects of loss of capture, thereby effectively providing continuous capture management in any heart chamber without encountering the limitations normally associated with evoked response sensing. A pacing threshold search is triggered upon detecting a secondary indicator of loss of capture. Secondary indicators of loss of capture may be lead-related changes, changes related to the occurrence of atrial sensed events, changes related related to the occurrence of ventricular sensed or paced events, and/or changes related to a monitored physiological condition.

Cardiac pacing apparatus and method for continuous capture management

Embodiments of the invention provide systems and methods for an implantable medical device comprising means for selecting between an atrial chamber reset (ACR) test and an atrioventricular conduction (AVC) test to provide atrial capture management and means for switching between an atrial-based pacing mode and a dual chamber pacing mode based on detecting relatively reliable atrioventricular conduction.

Atrial capture management in minimal ventricular pacing system and method

A cardiac stimulation system and associated capture management method are provided in which a safety factor, used in setting pacing pulse output energy, is automatically adjusted in response to the detection of indicators of a likely increase in pacing threshold. The method includes monitoring for increased pacing threshold indicators, which may also be associated with a compromised ability to perform a pacing threshold search. Such indicators may include, but are not limited to, the presence of arrhythmias, arrhythmia episode duration, pacing mode switches, refractory sensed events, and/or lead impedance changes. In response to the detection of a selected indicator of increased pacing threshold, the safety factor is automatically increased. After an increased pacing threshold indicator has not be detected for an interval of time, or if a pacing threshold search yields a result, the safety factor may be restored to a programmed value.

Dynamic adjustment of capture management 'safety margin'

Impedance, e.g. sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change. Other methods vary the AA interval to maximize impedance change over the entire cardiac cycle or during the atrial cycle.

Algorithm for the automatic determination of optimal pacing intervals

Techniques for increasing the accuracy of detection of atrial capture may involve determining a ventricular sensing window for ventricular senses associated with atrial test pulses based on observed ventricular senses. For example, an implanted medical device may deliver atrial test pulses to a patient at a time prior to respective atrial pacing pulses to evaluate atrial capture. The implanted medical device observes ventricular senses in response to the atrial test pulses. The implanted medical device may determine a point such as, for example, a midpoint of the ventricular sensing window for the ventricular senses and shift a midpoint of the default ventricular window to the determined midpoint. Further, the implanted medical device may measure patient parameters, such as heart rate and activity level, and determine a ventricular sensing window for ventricular senses associated with atrial test pulses based on the observed ventricular senses and measured patient parameters.

Atrial capture detection via atrial-ventricular conduction

An implantable medical device (IMD) includes both evoked response and algorithmic based threshold testing methodologies. The leads used with the IMD are evaluated to determine whether they are high or low polarization. The evoked response methodology is only utilized if the leads are low polarization.

System and method for capture management

A capture detection algorithm detects and distinguishes atrial capture. Atrial chamber reset (ACR) and AV conduction (AVC) algorithms are implemented to measure an atrial pacing threshold The data that is used to choose between ACR and AVC methods is used to determine the progression of the patient's disease state. Some of the significant aspects of the invention include enablement of accurate threshold measurements, including calculation of stability criteria, precise interval measurements and the use of reference interval to determine capture and loss of capture.

Capture management improvements

Algorithm for the automatic determination of optimal AV an VV intervals

In an atrial pacing system, the A-PACE pulse energy, defined by the pulse width and pulse amplitude, sufficient to reliably capture the atrium without being wasteful of battery energy is periodically determined in accordance with atrial capture management (ACM) algorithms. The ACM algorithms allow a slow intrinsic atrial heart rate that is suppressed by delivered A-PACE pulses resulting in A-CAPTURE and that occurs when delivered test A-PACE pulses result in ALOC to be detected. ALOC is declared if an A-EVENT of the slow intrinsic atrial heart rate is detected either during an ACM test window timed from the last delivered test A-PACE pulse or during delivery of a sequence of test A-PACE pulses delivered within or defining the ACM test window correlated to the slow intrinsic atrial heart rate.

Atrial capture management during atrial and ventricular pacing

A capture detection algorithm in which atrial capture is detected and distinguished. Further, an immediate measurement of the capture threshold is implemented when a pacemaker switches a lead's polarity from bipolar to unipolar in response to a detected lead failure, in either one or both chambers. Atrial chamber reset (ACR) and AV conduction (AVC), implemented to measure an atrial pacing threshold, are comparatively measured to enable measurement of the atrial pacing threshold. The data that is used to choose between ACR and AVC methods is used to determine the progression of the patient's disease state. Some of the significant aspects of the invention include enablement of accurate threshold measurements, including calculation of stability criteria, precise interval measurements and the use of reference interval to determine capture and loss of capture.

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.

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Woodbury, MN, United States of America

John C Rueter