ISO/TS 22077-3:2015
(Main)Health informatics — Medical waveform format — Part 3: Long term electrocardiography
Health informatics — Medical waveform format — Part 3: Long term electrocardiography
ISO/TS 22077-3:2015 defines the application of medical waveform format encoding rules (MFER) to describe long-term electrocardiogram waveforms measured in physiological laboratories and health care clinics. It covers electrocardiograms 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 the medical waveform format Encoding rules (MFER) Technical Specification (ISO 22077‑1).
Informatique de santé — Forme d'onde médicale — Partie 3: Électrocardiographie de longue durée
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TECHNICAL ISO/TS
SPECIFICATION 22077-3
First edition
2015-08-01
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/TS 22077-3:2015(E)
©
ISO 2015
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ISO/TS 22077-3:2015(E)
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ISO/TS 22077-3:2015(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 . 3
5.1 Primary description. 3
5.1.1 Sampling attributes . 3
5.1.2 Frame attributes . 4
5.1.3 Waveform class . 4
5.2 Data alignment . 5
5.2.1 Data encoding . 5
5.2.2 Recorder encoding . 6
5.2.3 Scanner encoding . 9
5.3 Lead name .12
5.4 Lead calculation .13
5.5 Filter information .14
5.5.1 Description of filter-processed data .14
5.5.2 Description of filter use information .15
5.6 Unique identifier .15
6 Measurement information .15
6.1 Measurement date/time .15
6.2 Patient information .15
6.2.1 Patient name .15
6.2.2 Patient ID .16
6.2.3 Age and date of birth .16
6.2.4 Gender .16
6.2.5 Comment.17
Annex A (informative) MFER Conformance statement .18
Annex B (informative) Waveform encoding .19
Annex C (informative) Example of waveform coding.21
Annex D (informative) Reference table of coding scheme .25
Bibliography .29
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ISO/TS 22077-3:2015(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
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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
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For an explanation on the meaning of ISO specific terms and expressions related to conformity
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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 22077-3:2015(E)
Introduction
The ambulatory 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, becomes commonly used and it strongly requires Ambulatory ECG examination for
the therapeutic purpose. However, new digitalized data of Ambulatory ECG recorder cannot be used
among different manufacturers scanner. This Technical Specification intends that MFER encoded data
for ambulatory ECG is analysed by other scanner and these are also interoperable on EMRs.
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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ISO/TS 22077-3:2015(E)
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 22077-3:2015(E)
Health informatics — Medical waveform format —
Part 3:
Long term electrocardiography
1 Scope
This Technical Specification defines the application of medical waveform format encoding rules (MFER)
to describe long-term electrocardiogram waveforms measured in physiological laboratories and health
care clinics. It covers electrocardiograms 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 the medical waveform format Encoding rules (MFER) Technical Specification (ISO 22077-1).
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, Medical waveform format — Part 1: Encoding rules
3 Terms and definitions
3.1
recorder
recording equipment worn or carried by the patient including associated electrodes and cables for
recording or recording and analysing heart action potentials
Note 1 to entry: Some recorders can record not only ECG but also non-invasive blood pressure measured
automatically, SpO2, and respiratory waveform.
3.2
scanner
equipment that retrieves ECG waveforms from the recorder and analyses and edits ECG waveforms
provided by the recorder to determine the presence of abnormal heart rhythms such as arrhythmia
3.3
patient event
information or event for analysing the ECG.
EXAMPLE For example, they may have chest pain, dizziness, or palpitatins, etc. Pushing a “patient event”
switch located on the recorder allows for recording ECG waveforms with the time of occurrence.
3.4
heart beat
ECG cycle, comprising the P,QRS and the ST-T wave
3.5
dominant beat
typical heart beat used for measurement and analysis
Note 1 to entry: In general, it is decided for heart beat excepting extrasystole or drifts of baseline.
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3.6
average beat
typical heart beat used for measurement and analysis
Note 1 to entry: This is averaged for waveforms excluding abnormal beats for each lead.
3.7
abstract waveform
one heartbeat of P-QRS-T, extracted by each lead for analyzing and editing
3.8
low battery
battery voltage is low and exchange of battery is required
3.9
leads off
electrodes are disconnected
3.10
out of range
poor condition on the radio field
3.11
pacing pulse
pulsed waveform from artificial pacemaker
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
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ISO/TS 22077-3:2015(E)
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.
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
Sampling rate 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 of least significant bit for ECG waveform sampled (generally, digitized)
(Table 3).
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ISO/TS 22077-3:2015(E)
Table 3 — Sampling resolution
Duplicated
MWF_SEN Data length Default Encoding range/remarks
definitions
Sampling resolution unit 1 —
-128~+127
12 0Ch Exponent (10th power) 1 See Table 6 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
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 attributes 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 class
Long-term ECG waveform is grouped based on instruments and purpose, as shown in Table 8.
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Table 8 — Waveform class
MWF_WFM Date 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.
For types of waveforms (Tables 9 to 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
Electrocardiogram 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 may have different display format for
each waveform type. However, this recommendation is not a requirement.
b) In addition, extracted waveforms which 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 ambulatory ECG
Dominant beat extracted
Electrocardiogram ECG_BEAT 9
waveform Write comment
Average, Median, Dominant
5.2 Data alignment
Data alignment recommended by ambulatory ECG standard shall be prescribed. Data alignment should
be simple as much as possible in order to prevent troubles caused by the complication which may result
in some limitation of interoperability by using complicated format.
5.2.1 Data encoding
In long-term ECGs, the recorder for recording ECG waveforms, the scanner for analysing and editing
ECG waveforms, and the electronic medical record for referring waveforms shall be encoded in the
most appropriate format respectively 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 prescribed.
— 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.
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ISO/TS 22077-3:2015(E)
5.2.2 Recorder encoding
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 to allow for reading 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.
5.2.2.1 Encoding of waveforms
In recorder encoding, waveforms shall be encoded according to 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.
Figure 1 — Encoding of waveform
MWF_END (80h) tag shall be encoded at the end of the file as a stopper.
In encoding waveforms, it is practical to use a multiple frame.
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 the 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.
5.2.2.2 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”.
Table 11 — Waveform information (status)
MWF_DTP Data length Default Remarks Duplicated definitions
10 0Ah 1 N.A. Override
Table 12 — Definition of data type
Value Data type
4 16-bit status
Pacemaker information shall be encoded with 16-bit status.
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ISO/TS 22077-3:2015(E)
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 event 1 0: none 1: patient event 1
9 Patient event 2 0: none1: patient 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 event 1 is defined on the assumption that the recorder event key is held down in ambulatory
ECGs. In the patient monitoring system, this corresponds with the “nurse call” in the transmitter.
Patient event 2 can be used as medical information. It is recommended that its practical use is defined
by each user.
5.2.2.3 Encoding of event information
Said “event information” includes every information except waveform information. Patient event is
defined as “Status” in 5.2.2.2 of this rule. Value of body movement, blood pressure, and SpO2 shall be
encoded as patient event.
Table 14 — Reference pointer
MWF_RPT Data length Default Remarks Duplicated definitions
Data type 1
69 45h Possible
Reference pointer Str < 256 URL
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ISO/TS 22077-3:2015(E)
Table 15 — Data type
Data type Value
External data 0
MFER data 1
Event information shall be encoded using the reference pointer MWF_RPT (45) in a number of formats.
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). It is recommended that MWF_END (80h) is used to encode not only waveforms but
also event information.
Using MWF_EVT (41h), patient event shall be defined as character string.
Figure 3 — Definition of event
Table 16 — Event
Duplicated defini-
MWF_EVT Data length Encoding range / remarks
tions
Waveform recognition Multiple definitions
2
pointcode available
Starting time (point) 4 Number of data values acquired
65 41h
at the sampling interval defined
Duration
4
in the root definition
Event information Str < 256
b) MWF_VAL (42h)
Figure 4 illustrates the encoding of patient event in event information by using the reference pointer
MWF_RPT (45). It is recommended that MWF_END (80h) is used to encode not only waveforms but also
event information.
This rule only applies to irregular measurements such as non-invasive blood pressure (NIBP). By using
MWF_VAL (42h), NIBP shall be defined as measurement value.
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Figure 4 — Definition of measurement value
Table 17 — Measurement v
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