Cardiac muscle resembles skeletal muscle in the striations and thus also known as striated muscles.  However, cardiac muscle is different in that cardiac muscle cells (cardiacmyocytes) do not fuse and thus the resulting fibers are not multinucleated.  Each cardiacmyocyte are however connected to one another via intercalated discs (a specialized junction) which allow for coordinated contraction.  These intercalated discs show up as lines that are particularly thick in comparison to the striations.  Notice also that each cell could branch off.

Another distinction in comparison to skeletal muscle is that these are involuntary muscles.