It usually means that the
heart has been working harder than it should be working. The
heart is a muscle, and like all muscles in our body, when worked hard they build mass. When the heart enlarges, it can cause problems with the efficiency factor of how your heart expels blood from one chamber of the heart to the next.
If you received that information, I'm guessing you had a procedure that made that determination. You are entitled to receive a written procedure report.