Medtronic, Inc.

Mattias Rouw

Peter M Van Dam

Willem Boute

Gustaaf A P Stoop

Douglas A Hettrick

Todd M Zielinski

Peter W Wohlgemuth

Patrick Scholten

Christianus J J E Van Groeningen

Diederick M Keizer

Henricus Willem M De Bruyn

Yong Kyun Cho

Shantanu Sarkar

Peter Oosterhoff

Henricus W M De Bruyn

Henk Westendorp

Dave J Munneke

Jos P A Smit

Gustaaf Stoop

Gustaaf AP Stoop

An implantable medical device operates to promote intrinsic ventricular depolarization according to a pacing protocol. When a cardiac rate exceeds a predetermined threshold, the implantable medical device modifies the pacing protocol parameters to promote AV synchrony.

Implantable medical device with ventricular pacing management of elevated heart rates

Techniques for estimating a cardiac chamber or vascular pressure based upon impedance are described. A device or system may measure an impedance between at least two electrodes implanted within or proximate to a cardiovascular system. The device or system may estimate a pressure of an element of the cardiovascular system based on a relationship between impedance and volume of the element, and based on a empirical relationship between the volume and the pressure. The device or system may also estimate the dimension of the element based on the impedance-volume relationship, or other characteristics based on the impedance. Because the impedance measurements may be obtained, in some examples, by using electrodes and leads implanted within the cardiovascular system and coupled to an implantable medical device, a practical estimation of a cardiovascular pressure can be obtained on a chronic basis without requiring the use other invasive sensors, such as micronanometer transducers.

Estimating cardiovascular pressure and volume using impedance measurements

This disclosure relates to monitoring intracardiac or vascular impedance to determine a change in hemodynamic status by detecting changes in an impedance parameter over cardiac cycles. An example method includes measuring a plurality of impedance values of a path within a patient over time, wherein the path includes at least one blood vessel or cardiac chamber of the patient, and wherein the impedance values vary as a function of blood pressure within the at least one vessel or chamber, determining a plurality of values of an impedance parameter over time based on the measured impedance values, wherein each of the impedance parameter values is determined based on a respective sub-plurality of the impedance values, comparing at least one of the impedance parameter values to at least one prior impedance parameter value, and identifying a change in a cardiovascular parameter related to the blood pressure based on the comparison.

Monitoring hemodynamic status based on intracardiac or vascular impedance

A method and system for detecting T-wave alternans for use in an implanted medical device uses wave transformation of QT intervals to obtain a reliable measure of TWA. In one embodiment, an array provides alternating sign multiplication factors which are applied respectively to n consecutive QT values. Each successive QT value is high pass filtered and moved sequentially through a queue so that each cycle each of the n QT values is multiplied by one of the factors; the products are summed and made absolute to provide an alternans match value. The alternans match is compared with a noise threshold signal, and alternans is declared when the match exceeds the threshold by a predetermined amount. The array is programmable and can be varied, providing a high degree of flexibility to optimize the test for the patient.

T-wave alternans train spotter

Waveform analysis is used to identify and distinguish components of a sensed input signal, such as P-wave and Far Field R-wave signal components present in a sensed cardiac signal, even when the components are so closely spaced in time that the overlap to create a distorted input signal. A set of composite waveforms are generated by superimposing waveform templates of the signal components with different time delays or degree of overlap. Form parameters for each composite waveform are derived and mapped in a multidimensional map, from which form parameter boundaries are derived. Waveform data is collected from an input signal during a sensed event time window, and form parameters for the input signal waveform are derived. An output identifying the signal component of interest (e.g., a P-wave) and its location within the sensed event time window is produced based upon the set of form parameters of the input signal waveform and the form parameter boundaries.

Form parameter forecaster for analyzing signals distorted by noise

An implantable medical device having a prioritized multiplexor sensing circuit used for monitoring the condition or status of a patient. The device includes patient parameter sensors, such as electrodes, that are monitored for indications of significant events. Sensors indicating the presence of significant events may then be monitored more often than the other sensors.

Prioritized multicomplexor sensing circuit

An implantable medical device operates to promote intrinsic ventricular depolarization according to a pacing protocol. The medical device operates to promote intrinsic conduction by providing elongated AV intervals or operating in an atrial based pacing mode. Conduction checks to determine if AV conduction is present are performed on a graduated or progressive scale to facilitate intrinsic emergence.

Implantable medical device with ventricular pacing protocol including progressive conduction search

An implantable medical device operates to promote intrinsic ventricular depolarization according to a pacing protocol. The medical device determines a course of action based upon the presence or absence of sensed ventricular activity. The device further determines whether that activity is properly conducted or the result of a PVC or nodal rhythm.

Implantable medical device with ventricular pacing protocol

A method and system nodal rhythm detection and treatment is provided. Detecting consecutive atrial events within a nodal activity window around ventricular events identifies nodal rhythm. Nodal rhythm is treated by calculating and applying a new atrial escape interval adjusted by the interval between the atrial and ventricular events.

Method and system for nodal rhythm detection and treatment

The invention is directed to methods and apparatus for automatically changing from bi-ventricular pacing, in which an implantable medical device (IMD) applies pacing stimuli to both ventricles of a heart during a cardiac cycle, to single-ventricle pacing, in which the IMD paces one ventricle and inhibits pacing of the other. An IMD applying the techniques of the invention automatically changes from bi-ventricular pacing to single-ventricle pacing, or vice versa, as a function of the reliability of left ventricular pacing. Exemplary techniques for determining the reliability of left ventricular pacing include impedance measurement, capture testing, capture threshold testing, or any combination thereof.

Bi-ventricular and single-ventricle pacing

Systems and methods for distinguishing a valid sensed cardiac signal from an invalid signal, such as a myopotential. In one embodiment, sensing an electrical signal with one electrode causes a timing window to commence. When the electrical signal is sensed by another electrode in the timing window, the sense is deemed valid. When the electrical signal is not sensed by the other electrode in the timing window, the sense is deemed invalid. Therapy may be adjusted when an inordinate number of senses are invalid.

Distinguishing valid and invalid cardiac senses

A method and system for nodal rhythm detection and treatment is provided. Detecting consecutive atrial events within a nodal activity window around ventricular events identifies nodal rhythm. Nodal rhythm is treated by calculating and applying a new atrial escape interval adjusted by the interval between the atrial and ventricular events.

The invention presents a medical device system and method for determining the degree of heart failure of a patient, utilizing information representative of dynamic variations in patient QT, or segments of QT, over time. The dynamic variations in QT that are measured relate to characteristics of the variation of QT with rate when rate is increasing and when it is decreasing. The dynamic variations include QT dynamic range, QT hysteresis, and QT directrix, each providing important information relating to the patient's variation of QT with heart rate, or QT(RR). QT and dynamic variations of QT can be measured in both left and right ventricles, and taken over the patient's normal rate range. The dynamic data is measured and stored periodically and compared with historical data to determine progression toward heart failure. In another embodiment, the QRST signals are divided into segments, namely QRS width; ST segment; and T wave width, and variations of these segments are analyzed to provide additional information indicative of the patient's heart condition. Preferably the system utilizes a microprocessor programmed to carry out an algorithm that weighs detected variations in QT, QT segments and/or QT dynamic parameters with time to track cardiac changes.

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Arnhem, Netherlands

Mattias Rouw