Echogenic foci within the left ventricle of the heart have been found in a minority of fetuses and generally are believed to be a normal variant. The cause and exact location of these foci have remained speculative, however.

I found this from a google search. It is from a journal of ultrasound. Just type in echogenic left ventricle of the heart and it is the first article. I hope this helps. Unfortunately I have no personal experience to add.