DICOM PS3.3 2021e - Information Object Definitions
A.34.3.4.9 Waveform Annotation Module

For Concept Name Code Sequence (0040,A043) in the Waveform Annotation Sequence (0040,B020) DCID 3335 “ECG Annotations” shall be used. This Context Group supports the annotation of suppressed pacemaker spikes in the ECG waveform.

DICOM PS3.3 2021e - Information Object Definitions