Can a very scary dream give you a heart attack? i heard that it has been shown true.

In theory sure..: In theory alot is possible. If a scary dream causes a rush of adrenaline, your heart starts racing and you have bad underlying disease, sure its possible. The thing to keep in mind is, its not the dream that caused the heart attack, it's the underlying heart disease that would be at fault.

Not sure...: There is something called "broken heart syndrome, " where a very severe stress can cause heart damage that looks very much like a heart attack. But, usually, very scary dreams do not cause heart attacks. Now, people with sleep disorders, like sleep apnea, can get heart rhythm problems. But that may be related to the sleep disorder and not the dream. The bad dream may also be from a sleep problem.