Can people really be Scared to Death?

Certainly!

Remember back in January this year it was reported that a back robber was charged with murder, he scared a 79-year-old grandmother, to death. Apparently he was looking for a place to hide and hid in the old lady's home.

So this what happen to our body. Our body have a natural protective mechanism called the fight-or-flight response. When faced with a life-threatening situation, the autonomic (involuntary) nervous system responds by increasing heart rate, increasing blood flow to the muscles, dilating the pupils, all of this increases the chances of survival.

How can the fight-or-flight response lead to death?
The autonomic nervous system uses the hormone adrenaline, a neurotransmitter, or chemical messenger, to send signals to various parts of the body to activate the fight-or-flight response. This chemical is toxic in large amounts; it damages the visceral (internal) organs such as the heart, lungs, liver and kidneys. It is believed that almost all sudden deaths are caused by damage to the heart. There is almost no other organ that would fail so fast as to cause sudden death. Kidney failure, liver failure, those things don't kill you suddenly.

What exactly happens in the heart when it's flooded with too much adrenaline?
Adrenaline from the nervous system lands on receptors of cardiac myocytes (heart-muscle cells), and this causes calcium channels in the membranes of those cells to open. Calcium ions rush into the heart cells and this causes the heart muscle to contract. If it's a massive overwhelming storm of adrenaline, calcium keeps pouring into the cells and the muscle just can't relax.

There is this specially adapted system of muscle and nerve tissue in the heart—the sinoatrial (SA) node, the atrioventricular node, and the Purkinje fibers—which sets the rhythm of the heart. If this system is overwhelmed with adrenaline, the heart can go into abnormal rhythms that are not compatible with life. If one of those is triggered, you will drop dead.

reference:
http://www.scientificamerican.com/article.cfm?id=scared-to-death-heart-attack

http://www.nydailynews.com/news/national/2009/01/29/2009-01-29_bank_robber_larry_whitfeld_in_murder_rap.html

* this is taken from my YA.
http://answers.yahoo.com/question/index;_ylt=AmXZhtnVwQ8wpJN54sjPnqjty6IX;_ylv=3?qid=20090809173458AAvP67U&show=7#profile-info-nDSXlKxnaa