It is a way of saying, but it is also real.

A broken heart can be a state of mind and a condition caused by grief. An intense emotional stress can trigger what is clinically known as takotsubo cardiomyopathy, a rare and temporary condition where part of a person’s heart suddenly becomes weakened or 'stunned', forcing the rest of the heart to work harder.

In this case the heart’s left ventricle changes shape, developing a narrow neck and round bottom. This is why it is called takotsubo, octopus in Japanese - it was first reported and described in Japan.

Among the causes there is the sudden and excessive release of hormones, usually adrenaline. All kind of stressful emotions come into play, with their destructive potential. Because instead of stimulating the heart, adrenaline can have the opposite effect, shutting it down.