Method of electrocardiographic signal processing and apparatus for performing the method
Inventors
Jurak, Pavel • Halamek, Josef • Viscor, Ivo • Piesinger, Filip • Vondra, Vlastimil • Smisek, Radovan • Leinveber, Pavel • Matejkova, Magdalena • Lipoldova, Jolana • Novak, Miroslav • Curila, Karol • Vesela, Jana • Prinzen, Frits W. • Nekuda, Ivo • Nekuda, Vit
Assignees
Cardian SRO • Cardion SRO • Institute Of Scientific Instruments Of Czech Academy Of Sciences V V I • St Anne's University Hospital Brno • Charles University
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Publication Number
US-11517243-B2
Publication Date
2022-12-06
Expiration Date
Abstract
A method of processing of electrocardiogram includes the steps of providing an electrocardiogram comprising signals in at least two channels; selecting at least two frequency ranges of the signal in each of the said at least two channels; calculating an envelope for the signal in each frequency range in each channel; dividing the calculated envelope of the signal in each frequency range in each channel into QRS complex segment envelopes; and computing an average or median envelope as an average or mean of QRS complex segment envelopes for each frequency range in each channel.
Core Innovation
The invention relates to processing a broad-band multi-channel electrocardiogram by selecting at least two frequency ranges in each signal channel and calculating an envelope for the signal in each frequency range and each channel. The calculated envelopes are divided into envelopes of segments of QRS complexes, and for each frequency range in each channel an average envelope or a median envelope is computed as an average or median of the QRS segment envelopes.
The frequency-resolved envelope signals are normalized by dividing the average envelope or median envelope by its integral or by a maximal value reached in the average envelope or the median envelope, with the integral or maximal value calculated within an interval of a minimum of 50 ms before and minimum 50 ms after the position of the QRS complex. After normalization, the invention calculates a signal average envelope or a signal median envelope from the normalized average envelopes or the normalized median envelopes of all frequency ranges within each channel.
The invention then determines a first temporal duration (Vdi) of the signal average envelope or the signal median envelope by using a horizontal line crossing the signal average envelope or the signal median envelope and calculating the time length of the horizontal line, where the horizontal line is placed at a level corresponding to 10–70 percent of a maximal value of the signal average envelope or the signal median envelope. The invention also determines a second temporal duration (AVdi) by using a horizontal line at the same 10–70 percent level and calculating the time length between the first and the last intersection of the signal average envelope or the signal median envelope with the horizontal line.
The method determines a local depolarization duration of heart ventricles in units of time as the first temporal duration, and/or a total local depolarization duration of heart ventricles in units of time as the second temporal duration. The measured and derived activation properties are used to define electrical activation characterization that is further refined with additional quantitative indices, including variability of durations (SDVd), volumetric activation index (AIi), variability of activation volume (SDAI), activation times (ATi), activation dyssynchrony (DYS), and derived relative and cumulative dyssynchrony measures (RDYS, PDYS) together with relative dyssynchrony variability (SRDYS).
Claims Coverage
The relevant independent claim is clm-00001 and it defines a multi-stage method that extracts QRS-aligned, normalized frequency-band envelope features per channel and derives temporal ventricular depolarization durations (Vdi and/or AVdi) from threshold-crossing intersections at a 10–70 percent level. It also requires a measurement apparatus with analogue amplifiers and analogue-to-digital signal converters having a transmission bandwidth at least 0.3 kHz, and it outputs results to at least one imaging unit.
QRS-segment envelope extraction over selected frequency ranges per channel
Selecting at least two frequency ranges of the signal in each of the said at least two channels; calculating an envelope for the signal in each frequency range in each channel; dividing the calculated envelope of the signal in each frequency range in each channel into envelopes of segments of QRS complexes; computing, for each frequency range in each channel, an average envelope or a median envelope as an average or median of the envelopes of segments of the QRS complexes.
QRS-window normalization of average/median envelopes by integral or maximal value
Normalizing the average envelope or the median envelope to obtain a normalized average envelope or a normalized median envelope for each frequency range in each channel by dividing the average envelope or the median envelope of each frequency range in each channel by its integral or by a maximal value reached in the average envelope or the median envelope, while calculating the integral or the maximal value within an interval of a minimum of 50 ms before the position of the QRS complex and minimum 50 ms after the position of the QRS complex.
Multi-band signal average/median envelope aggregation and threshold-duration extraction
Calculating a signal average envelope or a signal median envelope from the normalized average envelopes or the normalized median envelopes of all frequency ranges of the at least two frequency ranges within each channel; calculating a first temporal duration (Vdi) using a horizontal line crossing the signal average envelope or the signal median envelope and calculating the time length of the horizontal line at a level corresponding to 10-70 percent of a maximal value; and/or calculating a second temporal duration (AVdi) using a horizontal line placed intersecting the signal average envelope or the signal median envelope and calculating the time length between the first and the last intersection of the signal average envelope or the signal median envelope with the horizontal line at the same 10-70 percent level.
Temporal depolarization duration determination as local and total ventricular activation properties
Determining a local depolarization duration of heart ventricles in units of time as the first temporal duration, and/or determining a total local depolarization duration of heart ventricles in units of time as the second temporal duration.
Broad-band acquisition apparatus with transmission bandwidth at least 0.3 kHz and imaging output
Measuring the electrocardiogram comprising signals in at least two channels with an apparatus comprising analogue amplifiers connected to outputs of a sensor measuring the electrocardiogram signal and analogue signal to digital signal converters connected to outputs of corresponding analogue amplifiers, wherein the sensor, the analogue amplifiers, and the analogue-to-digital signal converters have the transmission bandwidth at least 0.3 kHz; performing the processing in a processing unit connected to the output of the analogue-to-digital signal converters and outputting to at least one imaging unit.
Across the independent claim, the core coverage centers on extracting QRS-aligned envelopes in multiple frequency ranges per channel, normalizing them using an integral or maximal value computed around the QRS position, aggregating across frequency ranges to obtain a channel-level signal average or signal median envelope, and deriving Vdi and/or AVdi as threshold-based temporal durations at a 10–70 percent level.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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