Hoamirror answering:  I noticed this same thing happening to me when taking a certain high blood pressure medication, Norvasc.  I would wake up with the horrible shortness of breath, pounding heart beat.  The slightest scary thing that happened in my dreams would cause this.  I told my doctor about this.  He just waved it off, as though what I said didn't mean anything to him.  I  knew that if I did not find the cause of this I would surely die in my sleep.  I went to a homeopath and was given skullcap for nerves.  It calmed my body so much that I was able to discontinue one of my high blood pressure meds (with my doctor's consent).  As you might have guessed, it was the Norvasc.  Never was I bothered with those bouts of pounding heart beats and shortness of breath again.  Somehow the Norvasc aggrevates the adrenal gland, which seems to cause too much adrenaline to be secreted.  My doctor died shortly after.  I had to find another doctor.  He prescribed another high blood pressure medicine which did the same as the Norvasc.  That med was Carvedilol.  Aside from those issues with the pounding heart beat and shortness of breath, this med worked great on my blood pressure.  Some of my other issues went away also...urine incontinence, which was great also.  But I could not stand feeling like I was dying every night from the other two negitives.  I asked by doctor to take me off this one also, after explaining these dying symptoms to him.  He was happy to do so.  He  said he had had a patient to die recently in his sleep.  I think the doctor has a very fast mind and may have made a connection.  I  told him to never let anybody tell him that a person died peacefully in their sleep.  Poppycock!   These episodes are anything but peaceful!!!  If any of you are taking some of these meds and are having these symptoms, you may want to ask your doctor to change your medications.  Some doctors are thoroughly taken with certain drugs and tend to prescribe them above all others.  They may even know about these horrible side effects of these dreams which cause these episodes.  It's your body and your health.