It’s called "Takotsubo cardiomyopathy," and is when a certain muscle of the heart begins to weaken resulting in acute heart failure, lethal ventricular arrhythmias, and ventricular rupture. Many call it simply “broken heart syndrome” because it often results after intense emotional stress.
Death or break-ups are the most common trigger event for broken heart syndrome causing the heart to become more and more unstable until the victim’s heart simply gives out. Broken heart syndrome usually begins with the swelling, or bulging, or the left ventricular apex. This is where the name takotsubo came from, which means “octopus pot” because of its shape and it was discovered in Japan.
There is a high circulation of catecholamine such as adrenaline or epinephrine, and results in significant blockages. Strangely enough after experiencing so much pain the bodies wary to cope is through the intense release of chemicals that slowly deteriorate the condition of the heart, resulting in a “broken heart” for many.