St. Jude Medical Ab

Telefonaktiebolaget Lm Ericsson (publ)

Pacesetter, Inc.

Telia Ab

Tomas Svensson

Kyungmoo Ryu

Stuart Rosenberg

Kjell Noren

Edward Karst

Sven-Erik Hedberg

Anders Bjorling

Stefan Hjelm

Malin Hollmark

Allen J Keel

Kjell Norén

Anders Björling

Karin Järverud

Andreas Blomqvist

Heidi Hellman

Jim Sundqvist

Erik Ekudden

Roar Hagen

Michael Broome

Johan Nystr&ouml;m

Andreas Karlsson

Per Johan Anders Nystr&ouml;m

Tor Bj&ouml;rn Minde

Bj&ouml;rn Stig Erik Johansson

A patient-specific hemodyanmic status model is determined from impedance data collected during periods of normal and abnormal hemodynamic status by deriving parameter values of a set of multiple impedance-derivable parameters from impedance signals collected during periods of normal hemodynamic status and in connection with periods of abnormal hemodynamic status. The parameter values are employed to estimate coefficients of a linear parametric status model. These coefficients can then be used together with parameter values determined from impedance signals determined during status assessment periods in order to determine a current hemdoynamic status of the patient.

Hemodynamic status assessment

Pacing related timing is determined for an implantable medical device (IMD) by pacing at an RV pacing site, a first LV pacing site and a second LV pacing site in accordance with a first site, a second site and a third site pacing order, and further in accordance with a first inter-electrode pacing delay between pacing at the first site and pacing at the second site and a second inter-electrode pacing delay between pacing at the second site and pacing at the third site. At least one of a sensed event or a paced event is detected for at each of the second site and the third site. The first inter-electrode pacing delay and the second inter-electrode pacing delay are adjusted to avoid sensed events in favor of paced events at each of the second site and the third site. An atrio-ventricular delay may also be adjusted to avoid sensed events or lack of capture due to possible fusion at the first site, in favor of paced events at the first site.

Systems and methods for determining pacing related parameters

An implantable medical device, is designed to collect a signal representative of the electric activity of the heart and determine a cardiogenic impedance signal for at least a portion of the heart. An R-wave detector of the IMD detects the timing of an R-wave during a cardiac cycle based on the signal representative of the electric activity. A minimum detector detects the timing of a cardiogenic impedance minimum in the cardiogenic impedance signal and within a systolic time window of the cardiac cycle. A detected arrhythmia is then classified by the IMD based on the timing of the R-wave detected by the R-wave detector and the timing of the cardiogenic impedance minimum detected by the minimum detector.

Arrhythmia classification

CRT settings for an implantable medical device are determined by applying pacing pulses to heart chambers of a scheme of different combinations of interchamber delays. A respective width parameter value representing an R or P wave width is determined for each such delay combination based on an ECG representing signal and the width parameter values are employed to estimate a parametric model defining the width parameter as a function of interchamber delays. Candidate interchamber delays that minimize the width parameter are determined from the parametric model and employed to determine optimal CRT settings. The technique provides an efficient way of finding optimal CRT settings when multiple pacing sites are available in a heart chamber.

Determination of cardiac resynchronization therapy settings

An implantable medical device is connectable to an epicardial left ventricular lead having at least one epicardial electrode and a myocardium penetrating catheter with at least one endocardial electrode and present in a lumen of the lead. The device comprises a pulse generator controller that controls a ventricular pulse generator to generate pulses to be applied to the epicardial and endocardial electrodes. The controller uses an endocardial-to-epicardial time interval or epicardial-to-endocardial time interval to coordinate endocardial and epicardial activation of the left ventricle to thereby achieve cardiac pacing that closely mimics the natural electrical activation pattern of a healthy heart.

Physiologically adapted cardiac resynchronization therapy

An implantable medical device () is configured for generating a cardiogenic impedance signal representative of the cardiogenic impedance of at least a portion of a heart () of a subject () during at least a portion of cardiac cycle. A moment processor () calculates a moment parameter value based on the cardiogenic impedance signal. The moment parameter is representative of a weighted sum of impedance amplitudes within a time window centered at defined time instance within the cardiac cycle. The weights of the impedance amplitudes are further dependent on the length in time between the defined time instance and the point of time of the associated impedance amplitude. The moment parameter is of high diagnostic value and is employed by an arrhythmia classifier () in order to classify a detected arrhythmia of the heart (), such as discriminate between hemodynamically stable or unstable arrhythmias and/or supraventricular or ventricular tachycardia.

Implantable medical device and method comprising means for detecting and classifying an arrhythmia

Techniques are provided for use with implantable cardiac stimulation devices equipped for multi-site left ventricular (MSLV) cardiac pacing. Briefly, intraventricular and interventricular conduction delays are detected for paced cardiac events. Maximum pacing time delays are determined for use with MSLV pacing where the maximum pacing time delays are set based on the conduction delays to values sufficient to avoid capture problems due to wavefront propagation, such as fusion or lack of capture. MSLV pacing delays are then set to values no greater than the maximum pacing delays and cardiac resynchronization therapy (CRT) is delivered using the MSLV pacing delays. In an example where an optimal interventricular pacing delay (VV) is determined in advance using intracardiac electrogram-based or hemodynamic-based optimization techniques, the optimal value for VV can be used as a limiting factor when determining the maximum MSLV pacing time delays.

Systems and methods for selectively limiting multi-site ventricular pacing delays during optimization of cardiac resynchronization therapy parameters

A device senses cardioelectrical signals using a right atrial (RA) lead, which might include far-field R-waves as well as near-field P-waves. The device concurrently senses events using a proximal electrode of an LV lead, which can sense both P-waves and R-waves as substantially near-field events. Suitable templates are then applied to the signals sensed via the proximal LV electrode to identify the origin of the signals (e.g. atrial vs. ventricular) so as to properly classify the corresponding events sensed in the RA as near-field or far-field events. In this manner, far-field oversensing is conveniently detected.

Systems and methods for detecting far-field oversensing based on signals sensed by the proximal electrode of a multipolar LV lead

The present invention provides methods for detecting phrenic nerve stimulation. A pacing module is instructed to deliver pacing pulses having a predetermined pulse amplitude and/or width within the refractory period of the left ventricle. The pacing pulses are repeatedly delivered during a number of cardiac cycles and wherein the pacing pulses are delivered at different delays relative to an onset of the refractory period of the left ventricle in different cardiac cycles. Impedance signals are measured in time windows synchronized with the delivery of pacing pulses in the refractory period of the left ventricle using at least one electrode configuration. At least one impedance signal is gathered from each time window, aggregated impedance signals are created using the impedance signals from the different time windows, and the aggregated impedance signals are analyzed to detect PNS.

Detection and reduction of phrenic nerve stimulation

The present invention provides implantable medical devices for detecting phrenic nerve stimulation. A pacing module is configured to deliver pacing pulses having a predetermined pulse amplitude and/or width within the refractory period of the left ventricle. The pacing pulses are repeatedly delivered during a number of cardiac cycles, and the pacing pulses are delivered at different delays relative to an onset of the refractory period of the left ventricle in different cardiac cycles. An impedance measurement module is configured to measure impedance signals in time windows synchronized with the delivery of pacing pulses in the refractory period of the left ventricle. A phrenic nerve stimulation, PNS, detection module is configured to gather at least one impedance signal from each time window, create aggregated impedance signals using the impedance signals from the different time windows, and analyze the aggregated impedance signals to detect PNS.

A decoder in a communication system using channel optimized vector quantization and including an encoder stores active encoder centroids c corresponding to active indices i, an active index being defined as an index that has a predetermined source probability p >0 of being selected by the encoder for transmission to the decoder, source probabilities p and the bit error rate epsilon to dynamically estimate a decoded vector using a sub-optimal algorithm in which only the most significant contributions are considered.

Decoding method and apparatus

A decoder improves delayed packet concealment in a packet network by using two decoder sections. A first decoder section bases its decoding during the concealment phase on erroneous filter states and a set of speech parameters, whereas a second decoder section bases its decoding on saved and updated filter states and the same speech parameters. The outputs of the two decoder sections are thereafter combined to form the final speech signal. This decoding strategy produces a speech signal with smooth transitions from delayed to non-delayed packets and uses information from the most recent packets for speech generation.

Delayed packet concealment method and apparatus

A channel optimized vector quantization apparatus includes a device for weighting a sample vector x by a weighting matrix A and a device for weighting a set of code book vectors &ccirc;,by a weighting matrix B. Device form a set of distance measures &lcub;d,(Ax,B&ccirc;,)&rcub; representing the distance between the weighted sample vector Ax and each weighted code book vector B&ccirc;,. Other device form a set of distortion measures &lcub;,(x)&rcub; by multiplying each distance measure by a channel transition probability P,that an index r has been received at a decoder when an index i has been sent from an encoder and adding together these multiplied distance measures for each possible index r. Finally device determine an index i,corresponding to the smallest distortion measure,(x) and represents the sample vector by this index i,.

Distance and distortion estimation method and apparatus in channel optimized vector quantization

The present invention relates to a method and arrangement for transforming phonemes over a shorter or longer time than an existing phoneme. The transformation takes place asymmetrically in that a basic phoneme is divided into a number of points, the said points being identified with respect to information-carrying elements in the phoneme. This provides a weighting in the phoneme between information-carrying elements and elements carrying less information. The parts of the phoneme which elements carrying less information are transformed over a longer or, respectively, shorter time interval. Elements in the phoneme which represent information-carrying parts are transferred unchanged in time. This provides a transformation of the phoneme which retains its original character in all essentials. By the parts of the phoneme carrying less information being identified, the invention also provides an indication of where different phonemes can be fitted into one another in the creation of artificial speech.

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Stockholm, Sweden

Tomas Svensson