DICOM PS3.3 2021e - Information Object Definitions
A.34.3.4.5 Number of Waveform Samples

The value of Number of Waveform Samples (003A,0010) in each Waveform Sequence (5400,0100) 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.

DICOM PS3.3 2021e - Information Object Definitions