Dying of a broken heart means to die from extreme sadness, grief and hopelessness. Commonly death by a broken heart occurs in romantic relationships, though can also be the result of a loss of intimate emotional attachment(s), rejection, deaths of family or friends or severe betrayal. Though in literary terms symptoms are easy listed, the true experience of suffering of a broken heart
is indescribable according to those who have experienced it firsthand.
Perhaps because it is an experience such as loss or love; It can only be understood if felt.
(I.e. A man's wife dies in a disastrous fire. Even though he tries to save her he is not able to get to her in time. Days go by and he has not eaten or slept or tried to contact family or friends. And work has failed to contact him, inquiring about his prolonged absence. Day and night he sits silently on the floor. At times crying hysterically and other times punching the walls and having violent fits. Within a week or a few days after, he dies from the overbearing and crushing grief
of the loss
of his beloved. Hence, "Died from a broken heart."
Once when I was young I watched a TV program that depicted young man and woman who fell in love rather quickly. It has been a long time since I saw the program, after it was six years ago. She left him, saying something along the lines of "we can't be together or she did not love him anymore." He spent three days wallowing in extreme grief, feeling rejected, alone and hopeless. After these three days he dies. If I am not mistaken it was a made up story. They traced its' origins and found the story to be mostly true. This man apparently "Died from a broken heart" according to the medical examiner and his apartment manager.