Operating Instructions
Contents
1. HRV Software Option Operating Instructions 4 1 Chapter 4 Review Time Domain Report Insert THRV Specific Times Selecting the Insert User button will allow you to enter up 25 individual time regions After an entry is inserted it will indicate a status of Not Analyzed Closing or printing the opened report will force all Un Analyzed HRV segments to be analyzed Enter Time HRV User Segment x Analyze Start Time Analyze Duration 10 23 87 12 10 00 AM 20 45 Segment Start Time Segment Duration HH MM 10 23 97 12 10 00 AM E Kj 4 Start Time Duration Add Update Remove Cancel Delete HRV Segment Selecting the Delete button will delete all highlighted HRV segments 4 2 HRV Software Option Operating Instructions Print HRV Report Print HRV Report The following pages are available to be printed at any time through the Print menu as part of the Print Specific Pages dialog The pull down menu shown below illustrates the print options h Vision Premier 3 Channel ECG Report MEE Z Beview Edit View Edit Print Close ReportSettings Window Help x ll slee e Print Report Ctrl P Print Forms Print Eull Disclosure Print User Inserted Strip pNN 50 Status 10 13 am W__ print Specific Pages 70ms 0 85 01 00 pm Vv SWE ents 47 ms 0 31 02 00 am TH Pm 39 ms 2 30 10 19 amw _ Print User HRV Segments 38 ms 0 23 11 00 am Wed 01 00 7542. bpm 16500 Tot Power 617 VLF Power 513 0 0033 0 04 Hz 11000 LF Power 47 0 04 0 15 Hz 5500 LFnu 44 9 HF Power 57 0 15 0 4 Hz 0 HFnu 55 1 0 0 0 1 0 2 0 3 0 4 0 5 LF HF 0 82 Frequency c b Print all Hourly HRY Seqments NUM Print Frequency Domain Summary Prints a summary page consisting of graphs for the maximum and minimum LF HF ratio segment plus tabulated automatic hourly measurements When viewing HRV information two new print menu items appear under the Print Menu These items will only be active if Frequency Domain hourly or user segments exist Print Hourly HRV Segments Prints all automatic hourly segments in a condensed graph form Print User HRV Segments Prints all user added segments in a condensed graph form HRV Software Option Operating Instructions 5 3 Chapter 5 Review Frequency Domain Report 5 4 HRV Software Option Operating Instructions Burdick Inc 500 Burdick Parkway Deerfield WI 53531 U S A 608 764 1919
3. may be added to Vision Series Holter Analysis Systems NOTE In this manual THRV describes Time Domain SHRV describes Frequency Domain and HRV describes both HRV Software Option Operating Instructions 1 1 Chapter 1 Introduction to HRV 1 2 Installing the Program NOTE The Vision Series Setup Guide contains additional information including requirements for installing and removing software and licenses Install License NOTE If you are installing the license onto a computer with Windows 95 or Windows 98 Second Edition then you must follow the instructions under Configure Environment Variables on pg 1 3 prior to installing the license Insert the license CD into the CDR drive Click on Start in the lower left corner on the screen Click Run Click Browse to locate Xinstall license bat where X is the drive designator for the CDR drive Click install license bat 6 Click Open Click OK The License software will install onto your system When the License installation is complete the system returns to the Windows desktop 8 Pressthe eject button on the CDR drive The Adaptec DirectCD Wizard appears Pane g 9 Ensure that the Leave the disc as it is option is selected CAUTION Selecting any other option may result in damage to the license CD 10 Click Finish and remove the CD disk from the CDR drive Remove License Follow the instructions under Install License above Fo
4. review the Time Domain HRV select HRV under the Review Edit menu The available operations will be to Insert User Delete and Analyze HRV segments The top section of the view displays a list of HRV segments where several columns of information are displayed Selecting an entry in the list will display that HRV segment s results in the lower right portion of the display Below is the current Time Domain View h Vision Premier 3 Channel ECG Report x E Beview Edit View Edit Print Close RepartSetings Window Help N x zs ael E Fel Time HRV Review Type Start Duration NN mean SDNN SDANN PNN gt 50 Status a Procedure 10 19 am Wed 23 12 872 ms 77 ms 70 ms 0 85 Day 01 00 pm Wed 04 00 893 ms 57 ms 47 ms 0 31 Night 02 00 am Thu 04 00 970 ms 61 ms 39 ms 2 30 Hourly 10 19 am Wed 00 41 762 ms 51 ms 38 ms 0 23 Hourly 11 00 am Wed 01 00 754 ms 69 ms 66 ms 0 21 Hourly 12 00 pm Wed 01 00 852 ms 36 ms 20 ms 0 31 Hourly 01 00 pm Wed 01 00 922 ms 34 ms 22ms 0 18 Hourly 02 00 pm Wed 01 00 916 ms 67 ms 56 ms 0 62 Hourly 03 00 pm Wed 01 00 855 ms 56 ms 43 ms 0 24 Hourly 04 00 pm Wed 01 00 883 ms 36 ms 22 ms 0 20 4 Delete Analyze Procedure RUD Start 10 19am Wed Duration 2312 3200 NNs 94225 2400 NNimean 872 ms SDNN 77 ms SDANN 70ms 1600 SDNNIDX 27 ms 800 NNNs 93477 rMSSD 21 ms 0 f pNN 50 0 85 0 0 0 4 0 8 ike 16 20 NN Interval sec For Help press F1 NUM
5. E mail Imoeller mdss com Deerfield Wisconsin 53531 U S A Telephone 49 511 62628630 800 777 1777 608 764 1919 Fax 449 511 62628633 Table of Contents Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Introduction to HRV ettet 1 1 OVERVIEW uu cedet Reed Ee ree t tus RR as e ie as 1 1 Intended Use 2 oer dende ES Evene P RUE 1 1 Installing the Program 510r Eyre EI eic ede 1 2 Description of Spectral HRV Analysis 2 1 DESP UOR uror irestene itor NA nerd teil tao ENA 2 1 Spectral Analysis Processing Functions sen 2 1 Changing HRV Configuration Parameters sess 2 2 Description of Time Domain Analysis 3 1 Descriptione 255 iet doe I RE E eed aen 3 1 Changing HRV Configuration Parameters sess 3 1 Review Time Domain Report 4 1 TARV View Suidae pied tee e E OO GO aiio en 4 1 Insert THRV Specific Times 0 0000 e cece 4 2 Delete HRV Segment soe 4 2 Print ARV REPON kinden EX e edt duse inde 4 3 Review Frequency Domain Report 5 1 SHRV MIeWE atas er vp eI DUE SUR UE Panis ade 5 1 Insert HRV Specific Times e 5 2 Delete HRV Segment ooo 5 2 Print HRV Segment nsv 5 3 HRV Software Option Operating Instructions ii HRV Software Option Operating Instructions Chapter 1 Introduction to HRV Overview The HRV software module uses previo
6. Low Frequency 0 0033 0 04 Hz 0 3 to 2 4 308 to 25 LF Low Frequency 0 04 0 15 Hz 2 4 to 9 25 to 6 6 HF High Frequency 0 15 0 40 Hz 9 to 24 6 6 to 2 5 Total Power upper limit 0 40 Hz 2 5 HRV Software Option Operating Instructions 2 3 Chapter 2 Description of Spectral HRV Analysis 2 4 Field Options Description R R Filters Min Max Section The Min Max RR sets the threshold for rejecting beats based on the RR interval Auto R R Pre Filter Enaple Rejects all normal R R that are less than 0 5 or greater than 1 5 of the previous accepted 8 beat Disable NN running average Default Minimum R R 300ms Ignores R R intervals which are less than the Msec Default threshold Range 0 500ms Maximum R R 3000ms Ignores R R intervals which are greater than the Msec Default threshold Range 500 3000ms Segment Type Time sec The segment type in combination with the Default segment size is used to define the min max length of the R R time series to process Beats Segment Size Minimum 50 to 10 000 default 300 Maximum 100 to 10 000 default 300 Maximum 0 to 99 The maximum percentage of correction allowed Corrected R Rs Default 20 to allow the segment to be processed AR Parameters With this technique the power spectral density is calculated after modeling the tachogram resampled or not to an autoregressive method The tachogram is as
7. Operating nStructions Vision Premier 3 Channel ECG Report E Beview Edit View Edit Print 2 amp Close Report Settings Window Help Start Frequency HRV Review LF HF Status For Help press F1 10 33 am Wed 11 01 am Wed 12 16 pm Wed 01 12 pm Wed 02 28 pm Wed 03 01 pm Wed 0421 pm Wed 05 04 pm Wed 06 46 pm Wed 07 00 pm Wed HRV Software Option Insert User 0 1 0 2 0 3 Frequency c b Start Duration RRs used corrected RR mean Tot Power VLF Power 0 0033 0 04 LF Power 0 04 0 15 Hz LFnu HF Power 0 15 0 4 Hz HFnu LF HF Vision Series Revision 0103 Operating Instructions Part No 086558 HR 10 39am Wed Hz 5 min 403 2 746 ms 80 bpm 617 513 4 448 5 55 1 DISCLAIMER BURDICK INC MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE CONTENTS OR USE OF THIS MANUAL OR WITH RESPECT TO ANY BURDICK INC HARDWARE OR SOFTWARE AND EXPRESSLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE Copyright 2003 Burdick Inc All rights reserved Authorized EC Representative Printed in the United States of America Medical Device Safety Service GmbH No part of this publication may be reproduced photocopied or Burckhardtstr 1 transmitted without the express written consent of the publisher D 30163 Hannover GERMANY PTE k Contact Ludger Moeller MEISS Arway
8. ini reports You can review on the display each individual epoch whether automatic or manual Additionally individual reports can be printed out The analysis parameters for performing a spectral computation are adjustable To change HRV Configuration parameters start the Vision Series application then 1 Click on System Settings in the menu bar 2 Click on the Freq HRV tab 3 Change the configuration parameters as required System Settings x Display Print Clinical Limits Auto Strips User Strips Freq HRV Time HRY System Frequency Domain Analysis Maximum Corrected RRs AR Parameters CONNEEN 20 099 Order Spectral Analysis Mode Segment ET Type to Output X 5 Time seconds 30 256 Distal atest Minimum RR Preprocessing Filter Interval Tachogram m 300 50 10000 E Data Correction Mode Maximum 300 Cubic Spline Interpolation i At ut bla FFT Parameters Window Size Pase Beuti 256 32 64 128 256 512 1024 2048 4096 Start Stop VLF 0 0033 os 04 Hz Window Overlap 50 0 93 LF 0 04 0 15 Hz Window Tile 0 15 0 4 Hz Blackman Harris Md Total 0 4 Hz Graph Smoothing 0 0 2 0 0 0 2 0 Medium Auto RR Pre Filter 300 Min RR Msec 0 500 3000 Max RR Msec 500 5000 owes HRV Software Option Operating Instructions Changing HRV Configuration Parameters Field Frequency Domain Analysis Options Off Default Auto Ma
9. ms 63 ms 66 ms 0 21 12 00 pm Wed 01 00 852 ms 36 ms 20 ms 0 31 01 00 pm Wed 01 00 922 ms 34ms 22ms 0 18 02 00 pm Wed 01 00 916 ms 67 ms 56 ms 0 62 03 00 pm Wed 01 00 855 ms 56 ms 43 ms 0 24 04 00 pm Wed 01 00 883 ms 36 ms 22 ms 0 20 m Insert User Delete eve Procedure AU Start 10 19am Wed Duration 23 12 3200 4 NNs 94225 2400 4 NNimean 872 ms SDNN 7 ms SDANN 70 ms Wea SDNNIDX 27 ms 8004 NNNs 93477 rMSSD 21 ms pNN 50 0 85 T T T 0 0 04 0 8 un 16 2 0 NN Interval sec Print all Hourly HRY Seqments NUM Print Time Domain Summary Prints a summary page consisting of Procedure day and night segment graphs and tabulated automatic hourly segments When viewing HRV information two new print menu items appear under the Print Menu These items will only be active if Time Domain hourly or user segments exist Print Hourly HRV Segments Prints all automatic hourly segments in a condensed graph form Print User HRV Segments Prints all user added segments in a condensed graph form HRV Software Option Operating Instructions 4 3 Chapter 4 Review Time Domain Report 4 4 HRV Software Option Operating Instructions Chapter 5 Review Frequency Domain Report SHRV Viewer To review Spectral Domain SHRV select HRV from the Review Edit menu The available operations will be to Insert User Delete and Analyze HRV segments The top section of the view display
10. ns After an entry is inserted it will indicate a status of Not Analyzed Closing or printing the current report will force all Un Analyzed HRV segments to be analyzed Enter Frequency HRV User Segment 10 23 87 12 10 00 AM 12 10 00 AM Thu Delete HRV Segment Selecting Delete will delete any highlighted HRV segments 5 2 HRV Software Option Operating Instructions Print HRV Segment Print HRV Segment The following pages are available to be printed at any time through the Print menu as part of the Print Specific Pages dialog The pull down menu illustrates the print options available while viewing HRV h Vision Premier 3 Channel ECG Report ef x Z Beview Edit View Edit Print Close ReportSettings Window Help EI x aj a Ar e E Print Report Ctrl P Print Forms Print Full Disclosure Print User Inserted Strip HFnu LF HF Status 10 33 am We print Specific Pages 551 0 82 11 01 am We z 44 0 127 12 16 pm We n Ls 58 5 0 71 01 12 pm We Print User HRY Segments 596 0 68 02 28 pm Wed 5 362 ms 48 8 51 2 0 85 03 01 pm Wed 5 795 ms 43 6 56 4 0 77 04 21 pm Wed 5 881 ms 58 5 415 1 41 05 04 pm Wed 5 883 ms 37 7 62 3 0 60 06 46 pm Wed 5 856 ms 44 9 55 1 0 82 07 00 pm Wed 5 726 ms 49 9 50 1 0 99 bs Insert User Delete Lese TE Start 10 39am Wed 27500 Hourly Duration 5 min RRs used 403 corrected 2 22000 RR mean 746 ms 80
11. nual Description Enables the SHRV analysis NOTE The Frequency Domain Analysis option can only be changed if the SHVR software is installed on the system SHRV software is used for research purposes only Spectral Analysis Mode Autoregression This parameter determines the spectral analysis technique to be performed FFT Default Data Processed Interval This parameter determines the data source Tachogram If Interval Tachogram is selected the direct R Default R event series is used and the output is in ms CPB Resampled If Resampled Time Series is selected for each Time Series second of time a linear interpolation is performed between the closest previous occurrence and the closest subsequent one The output is in BPM Hz Data Correction Cubic Spline This parameter determines if R R intervals Mode Interpolation should be corrected in areas of artifact noise Default PVCs and other non normal R R areas The Cubic Spline Interpolation technique None replaces a couple of missing R R intervals by Power Bands estimating a best cubic line fit between the two preceding and two subsequent good R Rs The Power is calculated for each band Defaults are listed below NOTE VLF information will not be displayed if duration of segment is less than 15 minutes VLF LF Total Power limits are adjustable with a range of 0 0 lt gt 2 0Hz Range Cycles Min Cycle Sec VLF Very
12. pled time series or an interval tachogram If the data correction mode of operation is enabled anomalies such as PVCs SVEs and some types of artifact are corrected with a spline matching technique The data correction algorithm will not correct across successive VE or SVE or if single VE or SVE occur within 3 beats to each other For AR analysis the input R R data can be filtered using operator selected filter types Smoothing of the output data should be per the selection in the HRV Software Option Operating Instructions 2 1 Chapter 2 Description of Spectral HRV Analysis 2 2 parameter file If the input data is resampled the output data is generally in units of MS Hz as a function of frequency in Hertz If the input data is left as an interval tachogram the output data is a function of cycles per beat CPB in units of MS CPB Changing HRV Configuration Parameters The Frequency Domain analysis can be configured for the following modes of operation The first mode OFF allows SHRV to be turned off The second mode of operation Automatic mode will automatically pick time segments and allow you to add specific times The third mode Manual mode only allows you to add specific times The automatic report for SHRV consists of a single page summary report which includes the hourly results The user added aspect allows you to manually select up to 25 individual time segments where each epoch could be printed out in individual m
13. port for THRV consist of a single page summary report which includes the procedure results day night results HRV Software Option Operating Instructions 3 1 Chapter 3 Description of Time Domain Analysis and hourly results A day night segment has been added to allow evaluation of the HRV during sleep and active conditions The user added aspect allows you to manually select up to 25 individual time segments where each epoch could be printed out in individual mini reports You can review on the display each individual epoch whether automatic or manual Additionally individual reports can be printed out The analysis parameters for performing a time domain are adjustable To change HRV Configuration parameters start the Vision Series application then 1 Click on System Settings in the menu bar 2 Click on the Time HRV tab 3 Change the configuration parameters as required Display Print Clinical Limits Auto Strips User Strips Freq HRY Time HRV System Time Domain Analysis a Segment Start Stop Day h m A eu Night GN AM p A AM 300 Min RR Msec 0 500 3000 Max RR Msec 500 5000 owes NOTE MinRR ignores R R intervals which are less than the threshold range 0 500ms Max RR ignores R R intervals which are greater than the threshold range 500 3000ms 3 2 HRV Software Option Operating Instructions Chapter 4 Review Time Domain Report THRV View To
14. r step 4 and step 5 locate and select the file remove license bat HRV Software Option Operating Instructions Installing the Program Configure Environment Variables If you are installing onto a computer with Windows 95 or Windows 98 Second Edition operating system then complete the following steps below before installing the license 1 2 3 4 Click Start in the lower left corner on the screen Click Run Type the following edit c config sys Click OK A text editor displays the contents of the config sys file Scroll to the end of the file If the following text does not appear add it to the end of the file SHELL C WINDOWS COMMAND COM C WINDOWS P E 2048 Click File and select Save Click File and select Exit Restart the computer HRV Software Option Operating Instructions 1 3 Chapter 1 Introduction to HRV 1 4 HRV Software Option Operating Instructions Chapter 2 Description of Spectral HRV Analysis Description The autonomic nervous system controls the heart Heart rate is controlled by a combination of parasympathetic and sympathetic nervous system influences The heart rate data can be analyzed in the frequency domain to determine the frequency components of the heart rate The parasympathetic respiratory activity creates a high frequency component 0 22 0 28 Hz of the spectrum heart rate data The sympathetic nervous system in conjunction with the parasympathetic nervou
15. riod are analyzed Only normal beats are analyzed Each time segment window displays a series of measurements described below NNs Number of normal R R intervals NN mean Mean of the normal R R intervals between two consecutive normal sinus beats in milliseconds SDNN Standard deviation of all normal R R intervals in the time segment SDANN Standard deviation of the mean of all 5 minute segments of normal R R intervals in the current time segment in milliseconds SDANNIDX Mean of the standard deviations of all normal R R intervals for all 5 minute segments of the selected time segment in milliseconds NNNs Number of adjacent normal intervals in the selected time segment rMSSD Root mean square of the successive differences square root of the mean of the sum of the squares of differences between the adjacent normal R R intervals over the selected time segment in milliseconds PNN gt 50 Percent of differences between adjacent normal R R intervals that are greater than 50 msec computed over the selected time segment Changing HRV Configuration Parameters The Time Domain analysis can be configured for the following modes of operation The first mode OFE allows THRV to be turned off The second mode of operation Automatic mode will automatically pick time segments and allow you to add specific times The third mode Manual mode only allows you to add specific times The automatic re
16. s a list of HRV segments where several columns of information are displayed Selecting an entry in the list will display that HRV segment s results in the lower right portion of the display Below is the current Frequency Domain View h Vision Premier 3 Channel ECG Report ef x B Beview Edit View Edit Print Close ReportSetings Window Help dj x Frequency HRY Review Hourly 10 39 am Wed 5 746 ms Hourly 11 01 am Wed 5 719 ms Hourly 12 16 pm Wed 5 854 ms Hourly 01 12 pm Wed 5 934 ms Hourly 02 28 pm Wed 5 962 ms Hourly 03 01 pm Wed 5 795 ms Hourly 04 21 pm Wed 5 881 ms Hourly 05 04 pm Wed 5 889 ms Hourly 06 46 pm Wed 5 856 ms 07 00 pm Wed 5 Insert User 443 56 0 415 40 4 48 8 43 6 58 5 37 7 443 Delete Status 55 1 0 82 440 1 27 58 5 0 71 59 6 0 68 51 2 0 95 56 4 0 77 41 5 1 41 62 3 0 60 551 0 82 af 27500 22000 16500 11000 5500 Start 10 39am Wed Hourly Duration 5 min RRs used 403 corrected 2 RR mean 746 ms 80 bpm Tot Power 617 VLF Power 513 0 0033 0 04 Hz LF Power 47 0 04 0 15 Hz LFnu 44 9 HF Power se 0 15 0 4 Hz HFnu 551 0 0 01 02 0 3 0 4 0 5 LF HF 0 82 Frequency c b For Help press F1 NUM HRV Software Option Operating Instructions 5 1 Chapter 5 Review Frequency Domain Report Insert HRV Specific Times Selecting the Insert User button will allow you to enter up 25 individual time regio
17. s system create a low frequency component 0 06 0 12 Hz Research indicates that decreased heart rate variability is an indicator of increased risk for sudden cardiac death Decreased heart rate variability is also an indicator of increased risk of cardiac death after acute myocardial infarction The relative interaction between the parasympathetic activity high frequency SHRV components and sympathetic activity low frequency SHRV components can be graphically displayed using the SHRV power spectral analysis technique The SHRV software performs frequency domain analysis utilizing Fast Fourier Transform FFT and autoregressive AR modeling frequency domain approaches Spectral Analysis Processing Functions The SHRV module calculates the power spectra utilizing FFT and or AR techniques for the specified data intervals utilizing the R R data contained in the QRS annotation input file The data is first processed by a qualification algorithm that finds the data interval with the least amount of artifact Example The operator selects a minimum time segment of 5 minutes and then selects a segment to be extracted from within a 60 minute region The qualification algorithm searches the entire 60 minutes to find the best 5 minute interval where no correction is needed If no such interval is found additional logic evaluates the region to find an interval requiring a minimum number of corrections The data to be processed can be a resam
18. sumed to be a single realization of a stationary random process of autoregressive type i e the value at the output of the process at a given time a single R R interval is a function of the outputs of the process at p previous AR time instances where p is the order of the model plus the synchronous value of an input white noise flat or constant power process When this modeling is possible which is NOT always the case the spectral density can be determined on the basis of the parameters of the model i e the weighting factors of the previous R R intervals in the regression In particular by considering the transfer function of the model the spectrum can be determined on the basis of the poles of the system These poles can be real or in complex conjugate pairs and they respectively imply a frequency component at zero or Nyquist frequency or at a frequency determined by the phase of the complex conjugate couple The estimation of the model parameters is performed with the Levinson Durbin Algorithm The whiteness test is performed by the Anderson test Once the Autocorrelation function of the error prediction sequence has been calculated the Anderson test checks how many times the estimated function overcomes a threshold if too many times the test is not verified HRV Software Option Operating Instructions Changing HRV Configuration Parameters Field Options Description AR Order Auto 0 This parameter determines
19. the frequency Default resolution of the AR modeling technique High values for this parameter will provide better 7 through 20 frequency resolution but can cause false frequency components to be generated A parameter of 0 causes the AR analysis to try to automatically determine the best model Setting the AR order to a value in the range of 7 to 20 will override automatic selection and force the selected order Some AR models usually with small number of orders may not generate any components that have a central frequency in the desired band and in this event the total power in the desired band is reported similar to standard FFT analysis In the event there are multiple components with a central frequency in the desired band the power reported will be the sum of all the bands To indicate an instance where no central frequency was found in a band an asterisk is displayed next to the reported power to Output 30 to 256 This parameter defines the output resolution of Default 50 the AR results R R Preprocessing None A DC filter is always used to remove the mean of Filter the R R data This prevents the DC component Linear from obscuring the higher frequency Default components contained in the data Additionally these optional filters can be applied Exponential to the R R interval data before the AR analysis is performed The linear filter first finds the regression line y 2 interc slope x i then sub
20. tracts the line The exponential filter first finds the fitting exponential then subtracts this exponential FFT Parameters The power spectral density is calculated with the technique of average Periodogram on overlapping windowed segments Nuttal and Carter approach The basic idea of this classical method is that the classical Periodogram by itself an estimate of the power spectral density is an unbiased but unfortunately inconsistent estimator Consistency is an essential characteristic of all estimators and it refers to the variance of the estimator itself to decrease with the increase of data used for the estimation As stated this is not the case for the Periodogram and that is why the averaged Periodogram is applied The variance is then inversely proportional to the number of estimates used and goes to zero for an infinite number of estimates The overlapping feature is not a requirement for the estimation but simply a way to increase the number of estimates given a fixed length tachogram and a specified FFT size NOTE the R R pre filter is not applied in the FFT mode HRV Software Option Operating Instructions 2 5 Chapter 2 Description of Spectral HRV Analysis Field Window Size Options 32 64 128 256 Default 512 1024 2048 4096 Description This controls the size of the window Window Overlap 0 to 99 This parameter determines the amount of overlap of adjacent windo
21. usly acquired ECG data The data will have been previously analyzed utilizing the Burdick Inc Arrhythmia detection algorithms included in the Vision Series Holter Analysis Systems This algorithm builds a QRS beat annotation file which contains the fiducial point and the classification of each ORS complex The analysis software supports a minimum 5 msec fiducial resolution The primary data input to the HRV module is the ORS beat annotation file The Vision Series systems have data viewers and editors which enable you to review the raw ECG data in conjunction with the resultant ORS annotation file data You can manually edit this data to override the automatic classification performed by the arrhythmia detection module Any editing of the ECG report will automatically force a recompile of HRV results upon accessing HRV information An HRV Time Domain Summary Report page and a Frequency Domain Summary Report page are printed along with the Final Report After you have finished editing Holter data review and edit the HRV report data as desired You can select the HRV option from Review Edit menu Intended Use NOTICE Computer assisted interpretation is a valuable tool when used properly However no automated interpretation is completely reliable and interpretations should be reviewed by a qualified physician before treatment or non treatment of any patient The Heart Rate Variability HRV module is an optional software feature which
22. ws when the average power spectrum is calculated The values represents the percentage of window overlap that is used during the spectral averaging operation mode It can be used to minimize data distortions caused by the non uniform amplitudes when some windowing functions are applied to the R R interval data A value of 50 should generally be used with the Blackman Harris and Hanning windows The rectangular window would generally use an overlap of 0 These values will minimize amplitude variations associated with the windowing and averaging processes Window Blackman Harris Default Rectangular This parameter is used to determine which type of window is used during the FFT spectral analysis These windows control the trade off between spectral resolution and side lobe leakage The default window is the Blackman Harris Hanning which provides minimal spectral leakage while providing good spectral resolution Hamming Graph Smoothing None This parameter is used to smooth FFT graphical results Low Medium Default High HRV Software Option Operating Instructions Chapter 3 Description of Time Domain Analysis Description The THRV report is updated each time the data is edited All individual results such as procedure day night and all individual segments are treated as independent analysis periods For HRV analysis all normal beats within the entire Holter analysis pe
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