ISO/TS 22077-2:2015

Health informatics — Medical waveform format — Part 2: Electrocardiography

ISO/TS 22077-2:2015 defines the application of medical waveform format encoding rules (MFER) to describe standard electrocardiogram waveforms measured in physiological laboratories, hospital wards, clinics, and primary care medical checkups. It covers electrocardiograms such as 12-lead, 15-lead, 18-lead, Cabrera lead, Nehb lead, Frank lead, XYZ lead, and exercise tests that are measured by inspection equipment such as electrocardiographs and patient monitors that are compatible with MFER. Medical waveforms that are not in the scope of this ISO/TS 22077-2:2015 include Holter ECG, exercise stress ECG, and real-time ECG waveform encoding used for physiological monitors.

Informatique de santé — Forme d'onde médicale — Partie 2: Electrocardiographie

General Information

• Status: Withdrawn
• Publication Date: 13-Aug-2015
• ICS: 35.240.80 - IT applications in health care technology
• Technical Committee: ISO/TC 215 - Health informatics
• Drafting Committee: ISO/TC 215/WG 2 - Systems and Device Interoperability
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 31-Aug-2023

Relations

• Revised: ISO 22077-2:2023 - Health informatics — Medical waveform format — Part 2: Electrocardiography
• Effective Date: 06-Jun-2022

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 22077-2
First edition
2015-08-01
Health informatics — Medical
waveform format —
Part 2:
Electrocardiography
Informatique de santé — Forme d’onde médicale —
Partie 2: Electrocardiographie
Reference number
ISO/TS 22077-2:2015(E)
©
ISO 2015

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ISO/TS 22077-2:2015(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
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ISO/TS 22077-2:2015(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
5 Encoding format . 2
5.1 Primary description. 2
5.1.1 Sampling attributes . 3
5.1.2 Frame attributes . 3
5.1.3 Waveform . 4
5.1.4 Channel . 6
5.2 Data alignment . 7
5.3 Abstract waveform. 7
5.4 Lead calculation . 8
5.5 Filter information . 9
5.5.1 Description of filter-processed data . 9
5.5.2 Description of filter use information . 9
5.6 Unique identifier . 9
6 Measurement information .10
6.1 Measurement date/time .10
6.2 Measurement time (classification point) .10
6.3 Measurement value .11
6.4 Measurement information classification .11
6.4.1 Observation event .11
6.4.2 Waveform ancillary information .11
6.4.3 Recording/display condition . .11
6.5 Power supply frequency .12
6.6 Electrode condition .12
6.7 Calibration waveform .12
6.8 Artefact contamination .12
6.9 Automatic interpretation code, etc. .13
6.9.1 MFER interpretation code and heart beat code encoding rules .13
6.10 Patient information .14
6.10.1 Patient name .14
6.10.2 Patient ID .14
6.10.3 Age and date of birth .14
6.10.4 Gender .14
6.11 Comment .15
Annex A (informative) MFER Conformance statement .16
Annex B (informative) Waveform alignment .17
Annex C (informative) Encoding of waveform recognition point and measurement values .26
Annex D (informative) Reference table of coding scheme .33
Annex E (informative) Waveform verification rule between ECG provider and user .37
Bibliography .38
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ISO/TS 22077-2:2015(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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 215, Health informatics.
ISO/TS 22077 consists of the following parts, under the general title Health informatics — Medical
waveform format:
— Part 1: Encoding rules
— Part 2: Electrocardiography
— Part 3: Long term electrocardiography
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ISO/TS 22077-2:2015(E)

Introduction
The standard 12-lead electrocardiogram (ECG) is one of the most widely used medical waveforms in
clinical sites. In particular, the increased usage of electronic medical records provides the environment
in which these ECGs can be accurately utilized; however, it is essential that to address the therapeutic
requirements, ECG use is not constrained to specific machine types and manufacturers. Furthermore,
there is great interest in the various kinds of patient information contained in ECGs that are extensively
studied and shared between health care providers.
This Technical Specification defines the detailed rules for electrocardiogram waveform format
that is encoded according to the medical waveform format encoding rules (MFER). In addition to
electrocardiogram waveform format encoding, there are rules for other waveforms such as long-term
ECG (Holter ECG), stress ECG, etc. that are contained in other MFER technical specifications. Please
refer to those specifications for additional information.
About MFER
Medical waveforms such as electrocardiogram, electroencephalogram, 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,
VCG, EEG with ECG, blood pressure with ECG, PSG, etc. MFER can describe not only ECG for physiological
examinations conducted in ICU and operating room acute care contexts, but also EEG, respiration
waveform, and pulse.
Simple and easy
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.
Using with other appropriate standards
It is recommended that MFER only describes medical waveforms. Other information can be described
using appropriate standards such as HL7, DICOM, 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, it is 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 are supported like filtering, view alignment and so on. In this way, the medical
waveform described in MFER can be used for multiple purposes.
Product capabilities are not limited
Standards often support only a minimum 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
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has mechanisms supporting not only a machine-readable coded system for abstract data, but also
human-readable representation.
The MFER specification can support 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.
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TECHNICAL SPECIFICATION ISO/TS 22077-2:2015(E)
Health informatics — Medical waveform format —
Part 2:
Electrocardiography
1 Scope
This Technical Specification defines the application of medical waveform format encoding rules (MFER)
to describe standard electrocardiogram waveforms measured in physiological laboratories, hospital
wards, clinics, and primary care medical checkups. It covers electrocardiograms such as 12-lead, 15-
lead, 18-lead, Cabrera lead, Nehb lead, Frank lead, XYZ lead, and exercise tests that are measured by
inspection equipment such as electrocardiographs and patient monitors that are compatible with
MFER.
Medical waveforms that are not in the scope of this Technical Specification include Holter ECG, exercise
stress ECG, and real-time ECG waveform encoding used for physiological monitors.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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 and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
dominant beat
typical heart beat used for measurement and analysis in standard 12-lead ECG
Note 1 to entry: In general, it is the primary heart beat excepting extrasystole or drifts of baseline.
3.2
average beat
typical heart beat used for measurement and analysis in standard 12-lead ECG
Note 1 to entry: This is averaged for waveforms excluding abnormal beats for each lead.
3.3
median beat
typical heart beat used for measurement and analysis in standard 12-lead ECG
Note 1 to entry: This is a waveform with the median value of waveforms excluding the abnormal beats for each
lead.
3.4
tag
identifier code for a semantic concept
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4 Symbols and abbreviated terms
CEN Comité Européen de Normalization/European Committee for Standardization
DBMS Data Base Management system
DICOM Digital Imaging and Communications in Medicine
ECG Electrocardiogram
EEG Electroencephalogram
EHR Electronic Health Record
GPS Global Positioning System
HL7 Health Level Seven
IEC International Electrotechnical Commission
IEEE Institute of Electrical and Electronic Engineers
JIS Japanese Industrial Standard
LSB Least significant bit
MFER Medical waveform Format Encoding Rules
MSB Most significant bit
OID Reference to the ISO standard
SAS Sleep Apnea Syndrome
SCP-ECG Standard Communications Protocol for Computerized Electrocardiography (ISO IS 11073-
91064)
SpO2 Saturation of Peripheral Oxygen
UID Reference to the ISO standard
UUID Reference to the ISO standard
VCG Vectorcardiogram
XML Extensible Markup Language
5 Encoding format
5.1 Primary description
MFER provides encoding of Long-term ECG waveforms but since MFER is used mutatis mutandis for
encoding of ECG waveforms such as ambulatory ECG, patient monitor system, etc., In addition, together
with encoding of ECG waveforms, encoding of information of recognition for waveform, measurement
information, interpretation information, etc. is provided, but these are all optional functions and
are dependent on each implementation concept. For instance, interpretation code or measurement
value might be described by other standard such as HL7, XML, DBMS, etc. with waveforms decoding
MFER. However, in all instances, when implementing a device, apply the requirements as listed in
ISO 22077-1.
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5.1.1 Sampling attributes
Sampling attributes including sampling rate and resolution are given in Tables 1 to 4.
5.1.1.1 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 defini-
MWF_IVL Default Encoding range/remarks
length tions
Unit 1 —
-128~+127
11 0Bh Exponent (10th power) 1 1 000 Hz 10 Override
Mantissa ≤4 e.g. unsigned 16-bit integer
The unit may 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 —
5.1.1.2 MWF_SEN (0Ch): Sampling resolution
This tag indicates the resolution, minimum bits, the medical waveform sampled (generally, digitized)
(Table 3).
Table 3 — Sampling resolution
Duplicated
MWF_SEN Data length Default Encoding range/remarks
definitions
Unit 1 —
-128~+127
12 0Ch Exponent (10th power) 1 See Table 4 10 Override
Mantissa ≤4 e.g. unsigned 16-bit integer
Table 4 — Sampling units
Unit Value Default Remarks
Voltage Volt 0 0,000 001 V —
5.1.2 Frame attributes
A frame is composed of data blocks, channels and sequences.
5.1.2.1 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
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5.1.2.2 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
5.1.2.3 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
MWF_SEQ Data length Default Remarks Duplicated definitions
06 06h ≤4 Depends on waveform data length — Override
5.1.3 Waveform
The waveform class and type, waveform attributes and waveform data are encoded as follows.
5.1.3.1 MWF_WFM (08h): Waveform class
Waveforms such as standard 12-lead ECG and monitoring ECG are grouped based on instruments and
purpose, as shown in Table 8.
Table 8 — Waveform class
MWF_WFM Data length Default Remarks Duplicated definitions
2 Non-specific waveform —
08 08h Override
Str ≤ 32 Waveform description —
As a general rule, each type of waveform is described in a separate specification.
For types of waveforms (Table 9), 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.
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Table 9 — Standard 12-lead ECG waveforms
Waveform kind Type Value Waveform description Remarks
Standard 12-lead ECG including
ECG_STD12 1 Standard 12-lead ECG general ECG in short-term record-
ing.
In general, one heart beat wave-
form extracted from standard
Electrocardiogram 12-lead ECG recording.
ECG_BEAT 9 QRS beat
Write comment
Average, Median, Dominant
Derived ECG from Frank vector
ECG_DRV 12 Derived lead
leads, EASI lead, etc.
5.1.3.2 MWF_LDN (09h): Waveform attributes (lead name, etc.)
This is the waveform code used in 12-lead ECGs and vector lead ECGs. Because the lead code is encoded
by 0 to 127, care should be taken when other standards such as SCP-ECG, etc. are followed. Since part of
these code spaces overlap, the present table shall be followed in all MFER applications.
Since in this specification, the code for the lead name is encoded by 127 or less, the codes specified in
systems such as SCP-ECG shall require conversion. However, in the present lead code table, leads which
are not used in standard 12-lead ECG are defined and, in general, will not need to be replaced.
Table 10 — Definition of waveform attributes
Data Description range, Duplicated
MWF_LDN Default
length remarks definition
Waveform code Data length = 2, if waveform
2
09 09h Undefined Override
information is encoded
Waveform information Str ≤ 32 —
The present code supports 12-lead electronic cardiogram waveforms. In this Technical Specification,
it is recommended to encode leads using MFER waveform information, rather than those specified in
other standards.
In addition, this Technical Specification extends the 12-lead names for humans to include ECG lead
names for animals. When other leads for animals are used, such as CV5RL, CV6LL, CV6LU, and V10, they
should be specified by waveform information.
Table 11 — Lead name
Code Lead Code Lead
1 I — —
2 II — —
3 V1 — —
4 V2 — —
5 V3 — —
6 V4 — —
7 V5 — —
8 V6 — —
9 V7 — —
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Table 11 (continued)
Code Lead Code Lead
b
10 — —
11 V3R 61 III
12 V4R 62 aVR
13 V5R 63 aVL
14 V6R 64 aVF
a
15 V7R 65 -aVR
16 X 66 V8
17 Y 67 V9
18 Z 68 V8R
19 CC5 69 V9R
20 CM5 70 D(Nehb Dosal)
— — 71 A(Nehb Anterior)
31 NASA 72 J(Nehb Inferior)
32 CB4 — —
33 CB5 — —
34 CB6 — —
a
  aVR lead shall not be encoded according to MFER.
The users (viewer) should mke a calculation to derive
–aVR when required.
b
  Although V2R (10) is defined in other rules such as
SCP-ECG, the definition shall not be used in MFER.
Code and information can be added to the type of waveform. If a waveform is required to be
reconfigured, as in the case of deriving leads III and aVF from leads I and II, the codes should always be
specified. The codes should be taken into special consideration as they have a function to specify some
processing, as in the case of deriving other limb leads from leads I and II or deriving a waveform based
on the lead name. See Annex D for the definition of waveform attributes.
As the lead names are defined depending on the class of waveform, the lead subsets are not called out
for each class of waveform in MFER. Thus, caution should be taken in encoding lead names.
For waveform codes, numbers 1 to 49151 (BFFFh) are already 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.
5.1.3.3 MWF_WAV (1Eh): Waveform data
The entire set of waveform data should be strictly aligned as defined in Frame attributes. If the
waveform data are compressed, the data alignment may depend on the compression method, but the
waveform data after un-compressing should be aligned according to the definition. Refer to Annex B.
If waveform data are different from what is defined in frame information, they may be discarded
depending on application processing. MFER behaviour is undefined in this case.
5.1.4 Channel
5.1.4.1 MWF_ATT (3Fh): Channel attributes (channel definition)
This tag defines the attributes for each channel (see Table 12). Before this definition, the channel
number shall be specified using the values in Table 6.
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Table 12 — Channel attributes
MWF_ATT Data length Default Remarks Duplicated definitions
63 3Fh Depends on definition — — Override
NOTE Channel definition for each channel is encoded with a special context tag of P/C = 1 and tag number of
1Fh. That is, the type number is P/C + tag number encoded with 3Fh and identifies the attribute of the relevant
channel.
For the tag of the channel attribute definition, context mode is selected with P/C (bit 6 = 1).
8 765 4 321
131(1Fh)
00 0Channel number
63(3Fh)
Figure 1 — Number of channel
The data length includes all the range of the channel attribute definition (Figure 2).
TagData length Group of definition
Channel attribute Channel attribute Channel attribute
—
Channel
3Fh All definition
number
TL VT LV —T LV
Figure 2 — Definition of channel attributes
TagData length Group of definition
Channel attribute Channel attribute
—
End-of-contents
Channel
3Fh 80h
number
TL VT LV —0000
Figure 3 — Definition of channel attributes with indefinite length
5.2 Data alignment
This Technical Specification supports many ECG alignment styles according to Annex B, allowing for
complicated alignment formats that could result in processing issues. It is recommended that formats
be simplified as much as possible in order to maximize interoperability.
5.3 Abstract waveform
This example is in principle the same as the 12-lead ECG, but one heartbeat of P-QRS-T is extracted and
expressed. The abstract waveform is processed in three ways: extraction as dominant beat, averaged
beat and median beat. These depend on the system concept and measurement method. The abstract
waveform should be clearly stipulated in implementation specifications, but all leads may be encoded
by abstract waveform of MFER.
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Figure 4 — Abst
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