33 results about "T wave alternans" patented technology

Embodiments of the present invention relate to implantable systems, and methods for use therein, that can detect T-wave alternans and analyze the detected alternans to provide information regarding cardiac instabilities and predict impending arrhythmias.

The invention disclosed includes a method and apparatus for calculation of T-wave alternas in electrocardiographic (ECG) signals; said method comprises the following method steps: (a) collecting and storing an ECG signal; (b) detecting each heartbeat T-wave in the ECG signal using an automatic detection and segmentation algorithm; (c) classifying said heartbeat T-wave as an even or odd heartbeat T-wave; (d) initializing said method by taking the first even and the first odd heartbeat T-wave as their respective initial average; (e) processing all the heartbeat T-waves in the ECG signal to generate an even heartbeat T-wave weighted average and odd heartbeat T-wave weighted average; and (f) calculating TWA using a distance metric between the even heartbeat weighted average and the odd heartbeat weighted average, said distance metric including curve matching Continuous Dynamic Time Warping (CDTW).

An implantable cardiac device that delivers electrical therapy to a patient's heart determines if a T wave alternan pattern of the patient's heart exists. The device includes a sensing circuit that generates an electrical signal including T waves representing paced electrical activity of the heart and a morphology detector that measures a metric of each T wave in the electrical signal. A T wave alternan pattern detector determines, responsive to the measured T wave metrics, if a paced activity T wave alternan pattern is present. The T wave alternan pattern detector may also detect for intrinsic T wave alternan patterns. A therapy control initiates suitable different responses for a paced T wave alternan pattern detection and an intrinsic T wave alternan pattern detection.

Embodiments of the present invention relate to implantable systems, and methods for use therein, that can detect T-wave alternans and analyze the detected alternans to provide information regarding cardiac instabilities and predict impending arrhythmias.

A method for generating a cardiac electrical instability assessment is disclosed herein. The method includes obtaining a short duration T-wave alternans (SDTWA) measurement, obtaining a long duration T-wave alternans (LDTWA) measurement, and obtaining a cardiac electrical instability assessment based on both the SDTWA measurement and the LDTWA measurement.

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.

Methods and systems for improved measurement of T-wave alternation in ECG signals are disclosed. The method and system includes receiving digitized ECG data (302) comprising a plurality of alternating consecutive odd and even beats, calculating (304) a variability for at least one of the odd or even beats and, according to a process of exclusion, dividing certain beats from T Wave alternation measurements are excluded (310).

The present invention belongs to the field of medical test technology, and the T-wave alternation measuring method for sports electrocardiogram beings from the No.113 beat of electrocardiogram signal and analyzes in 16 beats as one analysis window unit. Maximum heart rate is first judged to estimate the noise level. The power spectrum is then analyzed and judged based on noise, whether to exist obvious RR interphase alternation is judged, and if no, the ratio of component at 0.25 and the alternative component before deducing noise level is calculated. When the ratio is smaller than some value, obvious T-wave alternation is considered found out. The method of the present invention solves the problem of detecting weak T-wave alternation signal for predicting malignant arrhythmia.

The invention discloses an electrocardiosignal analysis method of a T wave alternans scatter diagram method based on morphology. Aiming at the defects of difficulty in detection of each heart beat T wave alternans amplitude value and complexity in calculation of T wave alternans detection by the spectrum analysis method, the T wave alternans scatter diagram method based on morphology is provided to provide a new effective quantitative index of T wave alternans detection for development of domestic related clinical researches. The method includes: using the T wave window analysis method for sampling T waves of 128 continuous heart beats selected from the American MIT-BIH standard heart beat irregularity database and the European ST-T electrocardio database, making a differential scatter diagram by the aid of the sample points, using vector angle index of the scatter diagram for quantitative analysis of T wave alternans to obtain a vector angle index range for judging whether T wave alternans exists or not, and comparing a T wave alternans detection result obtained by means of the vector angle index of the scatter diagram with the T wave alternans detection result obtained by means of the T wave alternans amplitude of the spectrum analysis method to judge reliability in detection of T wave alternans by the vector angle index.

A TWA measuring device, comprising: a grouping section configured to: group electrocardiogram waveforms of a subject under inspection in increments of a first beat number to generate a plurality of first groups; a storage section, the storage section configured to store electrocardiogram waveforms; a detection section configured to: detect a statistical difference between groups of measured values ​​of electrocardiogram waveforms of the first group; a heartbeat condition determination section configured to: determining that the heartbeat condition is unstable when there is a significant statistical difference between one group; and a TWA measurement section configured to measure the heartbeat using the stored electrocardiogram waveform when it is determined that the heartbeat condition is unstable changes on.

Embodiments of the present invention relate to implantable systems, and methods for use therewith, for assessing a patients' myocardial electrical stability. Implanted electrodes are used to obtain an electrogram (EGM) signal, which is used to identify periods when the patient experiences T-wave alternans. Additionally, the EGM signal is used to determine whether premature ventricular contractions (PVCs) cause phase reversals of the T-wave alternans. The patient's myocardial electrical stability is assessed based on whether, and in a specific embodiment the extent to which, PVCs cause phase reversals of the T-wave alternans. This abstract is not intended to be a complete description of, or limit the scope of, the invention.

The invention discloses a method for detecting TWA (T wave alternans) in the electrocardiogram and belongs to the technical field of medical testing. The method comprises the following steps of: eliminating data sections with excessively high noise from selected electrocardiosignals by judging in the earlier stage so as to obtain relatively stable data suitable to analyze and carrying out analysis by taking M beats as an analysis window; firstly, extracting a T wave matrix for the M beats of electrocardiosignals and then carrying out data fitting on T waves in the T wave matrix to obtain a novel T wave matrix; respectively calculating alternans correlation indexes by a correlation analysis method to obtain an ACI (Allowable Concentration Index) of the integral analysis window); then judging whether the TWA exists in the integral analysis window by the correlation analysis method; if the TWA exists in the integral analysis window, respectively carrying out least square linear fitting on sectional odd and even beats of the existing TWA and calculating an actual TWA quantity; and if the TWA does not exist in the integral analysis window, intercepting a next analysis window to carry out analysis. According to the invention, the TWA signals can be effectively detected from the time domain angle and the TWA quantity is accurately quantized.