A.34.3 12-Lead Electrocardiogram Information Object Definition

A.34.3.1 12-Lead ECG IOD Description

The 12-Lead Electrocardiogram (12-Lead ECG) IOD is the specification of digitized electrical signals from the patient cardiac conduction system collected on the body surface, which has been acquired by an ECG modality or by an ECG acquisition function within an imaging modality.

A.34.3.2 12-Lead ECG IOD Entity-Relationship Model

The E-R Model in Section A.34.1 of this Part applies to the 12-Lead ECG IOD.

A.34.3.3 12-Lead ECG IOD Module Table

Table A.34.3-112-Lead ECG IOD Modules

IE Module Reference Usage
Patient Patient C.7.1.1 M
Clinical Trial Subject C.7.1.3 U
Study General Study C.7.2.1 M
Patient Study C.7.2.2 U
Clinical Trial Study C.7.2.3 U
Series General Series C.7.3.1 M
Clinical Trial Series C.7.3.2 U
Frame of Reference Synchronization C.7.4.2 U
Equipment General Equipment C.7.5.1 M
Waveform Waveform Identification C.10.8 M
Waveform C.10.9 M
Acquisition Context C.7.6.14 M
Waveform Annotation C.10.10 C - required if annotation is present
SOP Common C.12.1 M

A.34.3.4 12-Lead ECG IOD Content Constraints

A.34.3.4.1 Modality

The value of Modality (0008,0060) shall be ECG.

A.34.3.4.2 Acquisition Context Module

For SOP Instances of ECG acquired in the cardiac catheterization lab, the Defined Template for Acquisition Context Sequence (0040,0555) is TID 3403. For routine resting or stress ECG, the Defined Template for Acquisition Context Sequence (0040,0555) is TID 3401.

A.34.3.4.3 Waveform Sequence

The number of Waveform Sequence (5400,0100) Items shall be between 1 and 5, inclusive.

A.34.3.4.4 Number of Waveform Channels

The value of the Number of Waveform Channels (003A,0005) in each Waveform Sequence Item shall be between 1 and 13, inclusive. The total number of channels encoded across all Items shall not exceed 13.

Note: This specialization provides for up to five Waveform Sequence Items (multiplex groups), with a total of 13 channels. This allows, for instance, encoding of four sets of three simultaneously recorded channels, the sets being acquired sequentially, plus one continuous channel for the duration of the other sets. This can be used to emulate the behavior of classical 12-lead ECG strip chart recorders with 4x3 presentation, plus a continuous lead II recording (see figure).

[pic]

Multiplex Group 1 - leads I, II, III; time offset 0; duration 2.5 sMultiplex Group 2 - leads aVR, aVL, aVF; time offset 2.5 s; duration 2.5 sMultiplex Group 3 - leads V1, V2, V3; time offset 5.0 s; duration 2.5 sMultiplex Group 4 - leads V4, V5, V6; time offset 7.5 s; duration 2.5 sMultiplex Group 5 - lead II; time offset 0; duration 9.84 s

FIGURE A.34.3-1 12-Lead ECG Example (Informative)

A.34.3.4.5 Number of Waveform Samples

The value of the Number of Waveform Samples (003A,0010) in each Waveform Sequence Item shall be less than or equal to 16384.

Note: This allows over 16 seconds per channel at the maximum sampling frequency; if longer recordings are required, the General ECG IOD may be used.

A.34.3.4.6 Sampling Frequency

The value of the Sampling Frequency (003A,001A) in each Waveform Sequence Item shall be between 200 and 1000, inclusive.

A.34.3.4.7 Channel Source

The Baseline Context ID for the Channel Source Sequence (003A,0208) in each Channel Definition Sequence Item shall be CID 3001.

A.34.3.4.8 Waveform Sample Interpretation

The value of the Waveform Sample Interpretation (5400,1006) in each Waveform Sequence Item shall be SS.

A.34.3.4.9 Waveform Annotation Module

The Defined Context ID for the Concept Name Code Sequence (0040,A043) in the Waveform Annotation Sequence (0040,B020) shall be CID 3335. This Context Group supports the annotation of suppressed pacemaker spikes in the ECG waveform.