For Channel Source Sequence (003A,0208) in each Channel Definition Sequence (003A,0200) Item DCID 3003 “Hemodynamic Waveform Source”, DCID 3001 “ECG Lead” for surface ECG channels, or DCID 3090 “Time Synchronization Channel Type” for time synchronization channels shall be used. The Channel Source Code Value shall encode at minimum the metric (measured physical quality) and function (measurement or stimulus); unless otherwise specifically encoded, the default function shall be "measurement".

The Channel Source Modifiers Sequence (003A,0209) in each Channel Definition Sequence (003A,0200) Item shall be used to specify additional qualifiers of the semantics of the waveform source, including technique and anatomic location, if not encoded by the Channel Source Code Value. Technique, with terms from DCID 3241 “Hemodynamic Measurement Technique”, shall be specified in Channel Source Modifiers Sequence (003A,0209) Items prior to the cardiac anatomic location(s), with terms from DCID 3010 “Cardiovascular Anatomic Structure”, DCID 3014 “Coronary Artery Segment”, and DCID 3019 “Cardiovascular Anatomic Structure Modifier”. If technique is pullback, the sequence of anatomic locations shall be specified in ordered Channel Source Modifiers Sequence (003A,0209) Items (e.g., initial, transitional, and final locations).