ISO 22077-3:2023
(Main)Health informatics — Medical waveform format — Part 3: Long-term electrocardiography
Health informatics — Medical waveform format — Part 3: Long-term electrocardiography
This document defines the application of medical waveform format encoding rules (MFER) to describe long-term electrocardiography waveforms measured in physiological laboratories and health care clinics. It covers electrocardiography such as bipolar 2, 3-lead, 12-lead that are measured by medical equipment such as Holter electrocardiograph and patient physiological monitors that are compatible with MFER documents encoding rules (see ISO 22077-1).
Informatique de santé — Forme d'onde médicale — Partie 3: Électrocardiographie de longue durée
General Information
Relations
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 22077-3
First edition
2023-08
Health informatics — Medical
waveform format —
Part 3:
Long-term electrocardiography
Informatique de santé — Forme d'onde médicale —
Partie 3: Électrocardiographie de longue durée
Reference number
ISO 22077-3:2023(E)
© ISO 2023
---------------------- Page: 1 ----------------------
ISO 22077-3:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO 2023 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 22077-3:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 2
4 Encoding format . 3
4.1 Primary description . 3
4.1.1 General . 3
4.1.2 Sampling attributes . 3
4.1.3 Frame attributes . 4
4.1.4 Waveform class . 4
4.2 Data alignment . 5
4.2.1 General . 5
4.2.2 Data encoding. 5
4.2.3 Recorder encoding . 6
4.2.4 Scanner encoding . 9
4.3 Lead name .12
4.4 Lead calculation.13
4.5 Filter information . 14
4.5.1 General . 14
4.5.2 Description of filter-processed data . 14
4.5.3 Description of filter use information . 15
Annex A (informative) MFER conformance statement .16
Annex B (informative) Waveform encoding .17
Annex C (informative) Example of waveform encoding .20
Annex D (informative) Reference table of coding scheme .24
Bibliography .28
iii
© ISO 2023 – All rights reserved
---------------------- Page: 3 ----------------------
ISO 22077-3:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 215, Health informatics.
This first edition of ISO 22077-3 cancels and replaces ISO/TS 22077-3:2015, which has been technically
revised.
The main changes are as follows:
— Clause 3 has been updated;
— editorial corrections.
A list of all parts in the ISO 22077 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
© ISO 2023 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 22077-3:2023(E)
Introduction
The long-term electrocardiography (ECG) examination is widely utilized in the clinical field. This
rule applies for long-term waveform description such as ambulatory ECG, monitoring waveforms, etc.
Recently, EMR, or Electronic Medical Records, became commonly used and it strongly requires long-
term ECG examination for the therapeutic purpose. However, new digitalized data of long-term ECG
recorder cannot be used among different manufacturers scanner. This document intends that MFER
encoded data for long-term ECG is analysed by other scanner and these are also interoperable on EMRs.
This document defines the detailed rules for electrocardiography waveform format that is encoded
according to the medical waveform format encoding rules (MFER). In addition to electrocardiography
waveform format encoding, there are rules for other waveforms such as standard 12-lead ECG, stress
ECG, etc. that are contained in other MFER documents.
About MFER
Medical waveforms such as ECG, electroencephalography (EEG), and blood pressure waveforms
are widely utilized in clinical areas such as physiological examinations, electronic medical records,
medical investigations, research, education, etc. Medical waveforms are used in various combinations
and document types according to the intended diagnostic purpose. For example, ECG waveforms are
utilized extensively in the clinical arena, with resting 12-lead ECG being used the most. A cardiologist
makes diagnoses using 10 s to 15 s ECG waveform measurements; however, longer periods are
sometimes required to recognize patient heart conditions such as arrhythmia. Also, there are many
other methods using ECG such as Holter ECG, physiologic monitoring ECG, stress ECG, intracardiac ECG,
vectorcardiography (VCG), EEG with ECG, blood pressure with ECG, sleep polysomnography (PSG), etc.
MFER can describe not only ECG for physiological examinations conducted in intensive care unit (ICU)
and operating room acute care contexts, but also EEG, respiration waveform, and pulse.
— Implementation: MFER is a specialized representation for medical waveforms that removes
unnecessary coded elements (“tags”) for waveform description. For example, a standard 12-lead
ECG can be described simply only using a common sampling condition and the lead condition,
making waveform synchronization and correct lead calculation much easier.
— Use with other appropriate standards: it is recommended that MFER only describes medical
waveforms. Other information can be described using appropriate standards published by
1) 2) 3)
organization including HL7® , DICOM® , and IEEE® , etc. For example, clinical reports that
include patient demographics, order information, medication, etc. are supported in other standards
such as HL7® Clinical Document Architecture (CDA); by including references to MFER information
in these documents, implementation for message exchange, networking, database management that
includes waveform information becomes simple and easy.
— Separation between supplier and consumer of medical waveforms: the MFER specification
concentrates on data format instead of paper-based recording. For example, recorded ECG is
processed by filter, data alignment, and other parameters, so that the ECG waveform can be easily
displayed using an application viewer. However, the ECG recordings displayed as images are not
as useful for other purposes such as data processing for research investigations. A design goal of
MFER is that a waveform is described in raw format with as complete as possible recording detail.
When the waveform is used, appropriate processing of the data is supported such as filtering, view
alignment, etc. In this way, the medical waveform described in MFER can be used for multiple
purposes.
1) HL7 is the registered trademark of Health Level Seven International. This information is given for the convenience
of users of this document and does not constitute an endorsement by ISO of the product named.
2) DICOM is the registered trademark of the National Electrical Manufacturers Association for its standards
publications relating to digital communications of medical information. This information is given for the convenience
of users of this document and does not constitute an endorsement by ISO of the product named.
3) IEEE is a registered trademark of Institute of Electrical and Electronics Engineers, Inc. This information is given
for the convenience of users of this document and does not constitute an endorsement by ISO of the product named.
v
© ISO 2023 – All rights reserved
---------------------- Page: 5 ----------------------
ISO 22077-3:2023(E)
— Product capabilities are not limited: standards often support only a set of requirements, so
the expansion of product features can be greatly limited. MFER can describe medical waveform
information without constraining the potential features of a product. Also, medical waveform
display must be very flexible, and thus MFER has mechanisms supporting not only a machine-
readable coded system for abstract data, but also human-readable representation.
The MFER specification supports both present and future product implementations. MFER supports the
translation of stored waveform data that was encoded using other standards, enabling harmonization
and interoperability. This capability supports not only existing waveform format standards but can be
extended to support future formats as well.
vi
© ISO 2023 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 22077-3:2023(E)
Health informatics — Medical waveform format —
Part 3:
Long-term electrocardiography
1 Scope
This document defines the application of medical waveform format encoding rules (MFER) to describe
long-term electrocardiography waveforms measured in physiological laboratories and health care
clinics. It covers electrocardiography such as bipolar 2, 3-lead, 12-lead that are measured by medical
equipment such as Holter electrocardiograph and patient physiological monitors that are compatible
with MFER documents encoding rules (see ISO 22077-1).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 22077-1, Health informatics — Medical waveform format — Part 1: Encoding rules
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 22077-1 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1.1
recorder
equipment worn or carried by the patient with the intention of recording and analysing heart action
potentials
3.1.2
scanner
equipment that retrieves ECG waveforms from the heart recorder and analyses, edits the information
received to determine the presence of abnormal heart rhythms and reports
3.1.3
patient ECG recording event
manual marking of clinical information during ECG recording
Note 1 to entry: There shall be a “patient ECG recording event” switch on the recorder. It can be pushed to mark
and timestamp a clinical event affecting the assessment of the ECG waveform. For example, the patient can have
chest pain, dizziness or palpitation. Pushing a “patient ECG recording event” switch located on the recorder
allows for recording ECG waveforms with the time of occurrence.
1
© ISO 2023 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 22077-3:2023(E)
3.1.4
dominant beat
primary heart beat extracted from typical beats for each lead in a period of long-term ECG
Note 1 to entry: The dominant beat is used for measurement and analysis of ECG in the period and easily viewing
the change of ECGs for each period.
Note 2 to entry: In general, it is the typical heart beat excepting extrasystole or drifts of baseline.
3.1.5
average beat
beat waveform constructed from the average value of each temporal point in ECG across a number of
beats
3.1.6
median beat
beat waveform constructed from the median value of each temporal point in ECG across a number of
beats
3.1.7
leads off
disconnected electrodes
3.2 Abbreviated terms
CDA Clinical Document Architecture
DBMS Data Base Management system
DICOM Digital Imaging and Communication in Medicine
ECG Electrocardiography
EEG Electroencephalography
EMR Electronic Medical Record
HL7 Health Level Seven
ICU Intensive Care Unit
IEEE Institute of Electrical and Electronic Engineers
MFER Medical waveform Format Encoding Rules
NIBP Non-Invasive Blood Pressure
PSG Sleep Polysomnography
SCP-ECG Standard communication protocol — Computer-assisted electrocardiography (ISO 41064)
SpO Saturation of Peripheral Oxygen
2
VCG Vectorcardiography
XML Extensible Markup Language
2
© ISO 2023 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 22077-3:2023(E)
4 Encoding format
4.1 Primary description
4.1.1 General
This document provides the encoding of long-term ECG waveforms. It also supports encoding other ECG
waveforms such as ambulatory ECG and real-time physiological monitoring. In addition, along with the
ECG waveform encoding, the encoding of waveform recognition information, measurement information,
interpretation information, etc. is provided, but these are all optional functions and depend on each
implementation concept. For instance, interpretation codes or measurement values are described by
other standard including HL7 CDA, XML, and DBMS, etc. with waveforms decoding MFER. However, in
all instances, when implementing a device, apply the requirements as listed in ISO 22077-1.
In order to make effective use of this document, a MFER conformance statement is provided in Annex A
and sample waveform description are provided in Annex C.
4.1.2 Sampling attributes
4.1.2.1 General
Sampling attributes including sampling rate and resolution are given in Tables 1 to 4.
4.1.2.2 MWF_IVL (0Bh): Sampling rate
This tag indicates the frequency or sampling interval for the medical waveform is sampled (Table 1).
Table 1 — Sampling rate
Data Duplicated
MWF_ IVL Default Encoding range/remarks
length definitions
Sampling rate unit 1 —
-128 to +127
11 0Bh Exponent (10th power) 1 1 000 Hz 10 Override
Mantissa ≤ 4 e.g. unsigned 16-bit integer
The unit can be frequency in hertz, time in seconds or distance in meters (Table 2).
Table 2 — Sampling rate unit
Unit Value Remarks
Frequency Hz 0 Including power
Time interval s 1 —
4.1.2.3 MWF_SEN (0Ch): Sampling resolution
This tag indicates the resolution of least significant bit for ECG waveform sampled (generally, digitized)
(Table 3).
Table 3 — Sampling resolution
Data Duplicated
MWF_ SEN Default Encoding range/remarks
length definitions
Sampling resolution unit 1 —
See
12 0Ch Exponent (10th power) 1 -128 to +127 Override
10
Table 4
Mantissa ≤ 4 e.g. unsigned 16-bit integer
3
© ISO 2023 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 22077-3:2023(E)
Table 4 — Sampling units
Unit Value Default Remarks
Voltage Volt 0 0,000 001 V —
4.1.3 Frame attributes
4.1.3.1 General
A frame is composed of data blocks, channels, and sequences.
4.1.3.2 MWF_BLK (04h): Data block length
This tag indicates the number of data sampled in a block (Table 5).
Table 5 — Data block length
MWF_BLK Data length Default Remarks Duplicated definitions
04 04h ≤4 1 — Override
4.1.3.3 MWF_CHN (05h): Number of channels
This tag indicates the number of ECG channels (Table 6). If a previously specified channel attribute is
reset to the root definition including Default, the number of channels should be specified before each
definition of the channel attribute. The number of channels cannot be specified within the definition of
a channel attribute.
Table 6 — Number of channels
MWF_CHN Data length Default Remarks Duplicated definitions
05 05h ≤4 1 — Override
4.1.3.4 MWF_SEQ (06h): Number of sequences
This tag indicates the number of sequences (Table 7). If the number of sequences is not designated, it
depends on the data block length, the number of channels, and the number of waveform data values
that are defined for the specified frame.
Table 7 — Number if sequences
Duplicated defini-
MWF_SEQ Data length Default Remarks
tions
06 06h ≤4 Depends on waveform data length — Override
4.1.4 Waveform class
Long-term ECG waveform is grouped based on instruments and purpose, as shown in Table 8.
Table 8 — Waveform class
MWF_WFM Data length Remarks Duplicated definitions
2 — Override
08 08h
Str ≤ 32 Waveform encoding —
As a general rule, each type of waveform is described in a separate specification.
4
© ISO 2023 – All rights reserved
---------------------- Page: 10 ----------------------
ISO 22077-3:2023(E)
For types of waveforms (Tables 9 and 10), numbers 1 to 49151 (BFFFh) are reserved. Numbers 49152
to 65535 can be used privately, but it is recommended to add these to the MFER specification rather
than rely on private extensions.
Table 9 — Long-term ECG waveform-1
Major classification Type Value Waveform descriptions Remarks
Ambulatory ECG
Electrocardiography ECG_LTERM 2 Long-term ECG
Patient monitoring system ECG
a) It is recommended that ECG classified into the type ECG_LTERM is used when it takes over 30 min
for measurement, because application system such as viewer can have different display format for
each waveform type.
b) In addition, extracted waveforms that are used in the long-term ECG are shown in Table 10. These
waveforms shall be extracted after being analysed and edited, and then shall be used for scanning.
Table 10 — Long-term ECG waveform-2
Major classification Type Value Waveform descriptions Remarks
Extracted waveform for one
beat by long-term ECG
Electrocardiography ECG_BEAT 9 QRS waveform
Write comment
Average, Median, Dominant beat
4.2 Data alignment
4.2.1 General
Data alignment recommended by long-term ECG standard shall be specified. Data alignment should be
as simple as possible in order to prevent troubles caused by the complication which can result in some
limitation of interoperability by using complicated format.
4.2.2 Data encoding
In long-term ECGs, the recorder for recording ECG waveforms, the scanner for analysing and editing
ECG waveforms, and the EMR for referring waveforms shall be encoded in the most appropriate format
in accordance with MFER.
— Recorder encoding: The recorder encodes ECG waveforms on the assumption that it processes the
data in real time. The data encoded by the recorder shall be regarded as the original data (original
ECG). This encoding format is defined in view of the risk of sudden disconnection of battery or other
record media in patient’s daily life. Furthermore, encoding of information including pacemaker
spike and patient event shall be also specified.
— Scanner encoding: In the scanner encoding, information derived from analysing and editing the
long-term ECG data recorded by the recorder shall be added to the original data. This encoding
format is defined in view of reading MFER file with the scanner, and the secondary information,
including heart beat code or event strip created by the scanner, shall be encoded in this format.
This format also shall be used to output data from the scanner to the host system such as electronic
medical record in accordance with MFER.
5
© ISO 2023 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 22077-3:2023(E)
4.2.3 Recorder encoding
4.2.3.1 General
In recorder encoding, the following points should be noted:
— In view of sudden disconnection of battery or other record media, the data recorded by the time of
the disconnection should be kept in order to read data in a proper format.
— Information on patient event or body movement should be in the same way as ECG and respiratory
waveforms, so that every user can read data without any difficulty.
4.2.3.2 Encoding of waveforms
In recorder encoding, waveforms shall be encoded in accordance with MWF_WAV (1Eh), and shall
consist of lead, status and stopper. Figure 1 shows one-minute waveform data, and it is an example of
waveform data recorded using leads called CM5 and NASA. CM5 and NASA are part of the lead shown in
Tables 21, D.1, and D.2.Examples of status are shown in Table 22.
Figure 1 — Encoding of waveform
MWF_END (80h) tag shall be encoded at the end of the file as a stopper, see Annex B.
In encoding waveforms, it is practical to use a multiple frame.
Figure 2 shows the structure of multiple frame configurations.
It is practical to use multiple frames to encode waveforms. Frames are usually created in the order that
waveforms are generated, and then the frames shall be aligned to create waveforms.
Figure 2 — Multiple frame configurations
In encoding successive waveforms with multiple frames, waveforms encoded with frames later than
Frame 2 are usually the same with pre-encoded condition or status in Frame 1. For example, the
sampling frequency and waveform code are usually the same. In such case, according to MFER, the
header is frequently omissible.
4.2.3.3 Encoding format for pacemaker spike and patient event
Pacemaker spike and patient event shall be encoded by data type MWF_DTP (0Ah) “16-bit status”, as
shown in Tables 11 and 12.
6
© ISO 2023 – All rights reserved
---------------------- Page: 12 ----------------------
ISO 22077-3:2023(E)
Table 11 — Waveform information (status)
MWF_DTP Data length Default Remarks Duplicated definitions
10 0Ah 1 — — Override
Table 12 — Definition of data type
Value Data type
4 16-bit status
Pacemaker information shall be encoded with 16-bit status, as shown in Table 13.
Table 13 — Definition of status
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Bit Information Value
0 Pacing 0: none 1: Pacing
1 Reserved —
2 Ventricular pacing 0: none 1: Ventricular pacing
3 Atrial pacing 0: none 1: Atrial pacing
4 Reserved —
5 Low battery 0: none 1: Battery changing
6 Leads off 0: none 1: Electrode disconnection
7 Radio field strength 0: none 1: Out of range
8 Patient ECG recording event 1 0: none 1: patient ECG recording event 1
9 Patient ECG recording event 2 0: none 1: patient ECG recording event 2
10 - 12 Body position 000: none
001: Standing/Seating
010: Supine
011: Right lateral decubitus
100: Left lateral decubitus
101: Prone
110: Reserved
111: Reserved
13 Reserved —
14 Reserved —
15 Reserved —
Patient ECG recording event 1 is defined on the assumption that the recorder event key is held down
in long-term ECGs. In the patient monitoring system, this corresponds with the “nurse call” in the
transmitter. Patient ECG recording event 2 can be used as medical information. Its practical use should
be defined by each user.
4.2.3.4 Encoding of event information
Said “event information” includes every information except waveform information. Patient event is
defined as “Status” in 4.2.3.3 of this rule. Value of body movement, blood pressure, and SpO shall be
2
encoded as patient event.
7
© ISO 2023 – All rights reserved
---------------------- Page: 13 ----------------------
ISO 22077-3:2023(E)
Table 14 — Reference pointer
MWF_RPT Data length Default Remarks Duplicated definitions
Data type 1 —
69 45h — Possible
Reference pointer Str < 256 URL
Table 15 — Data type
Data type Value
External data 0
MFER data 1
Event information shall be encoded using the reference pointer MWF_RPT (45h) in a number of formats,
as shown in Tables 14 and 15. This tag indicates an external file pointer represented as a hyperlink.
Some examples are shown below:
a) MWF_EVT (41h)
Figure 3 illustrates the encoding of patient event in event information by using the reference pointer
MWF_RPT (45h). MWF_END (80h) should be used to encode not only waveforms but also event
information.
Using MWF_EVT (41h), patient event shall be defined as charact
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.