You could have downloaded CVSim 1.7 for Mac from our software library for free. The program lies within Education Tools, more precisely Science. The actual developer of this free software for Mac is PhysioNet.
From the developer:
CVSim is a lumped-parameter model of the human cardiovascular system that has been developed and used for research and for teaching quantitative physiology courses at MIT and Harvard Medical School since 1984. The versions presented here have a graphical user interface implemented in Java, with computational components in C.
You may want to check out more Mac applications, such as Genealogy Pro, sciatrope or Curvus Pro X, which might be similar to CVSim.