Computer Generated Cross Section 3d Model of Heart. You can get this model <a rel="nofollow" class="external text" href="https://www.cgtrader.com/3d-models/science-medical/medical/animated-realistic-human-heart-medically-accurate">here</a> and <a rel="nofollow" class="external text" href="http://www.turbosquid.com/3d-models/3d-model-human-heart-medically-accurate/1021860">here</a>. You can even watch it in 3d <a rel="nofollow" class="external text" href="https://sketchfab.com/models/168b474fba564f688048212e99b4159d">here.</a>
The original version from DrJanaOfficial takes 870ms (29 frames, 30ms), this one is derived from an earlier version with higher resolution and adjusted to take 966ms (42 frames, 23ms) to better show the motion.
<a href="//commons.wikimedia.org/wiki/User:DrJanaOfficial" title="User:DrJanaOfficial">DrJanaOfficial</a>
This file was derived from: <a href="//commons.wikimedia.org/wiki/File:CG_Heart.gif" title="File:CG Heart.gif">CG Heart.gif</a><br> higher resolution obtained from earlier revision