Certainly, echocardiographers should have the most detailed knowledge of this topic. However, all sonographers should have a good understanding of cardiac hemodynamics since it influences blood flow throughout the body.
For example, an abdominal sonographer will not be able to make much sense of the hepatic venous waveform if they do not have a good understanding of cardiac hemodynamics. The same is true for obstetrical sonographers and for vascular sonographers.
We all need to know how the heart works :)
You should definitely check it out.
If you would also like a little more detail on EKG and its interpretation, check out this video.