As an educator and sonographer, I have noticed an error in your presentation...
Very cute material, but I need to point out as an echocardiographer, that one of your 4 chamber views is incorrectly labelled. The right and left sides of the heart are inverted. You can see a moderator band in the image, and the Ventricle is smaller than the opposite ventricle, yet it is labelled the LV. It should be the RV on the left side of the screen , and it should be attached to the RA. The right sided chambers on the screen are the LV and LA.
Please correct this error.