Takotsubo cardiomyopathy is a condition which causes the heart to balloon (become enlarged) and weakened, resulting in the heart not pumping blood properly. Takotsubo is the name of a Japanese octopus trap, which is a similar shape to a heart with this condition.
In the following diagram, courtesy of Wikipedia, a heart with Takotsubo cardiomyopathy is shown in figure A, compared to a normal heart in figure B.