Flutter

Sometimes when I wake up from a nightmare
I feel on my chest (without touching) some sort of flutter about 150bpm but if I check my pulse on the neck or wrist it is normal around 60.
(I do have WPW and small prolapses, but this does not seem like it for me)

[Jerry_NJ]

From the information you give it sounds to me like your nightmare (hope this is a rare experience - or it may need attention on its own) causes some atrial flutter.  If the flutter signal don't make it through the sinus node (hope I got the part correctly named)  the ventricle will not be triggered into a high rate, thus the normal (I assume) 60 bpm.  

Given your known heart conditions I also conclude you have been examined by a doctor, perhaps a cardiologist.  If the (guessed?) 150 bpm reoccurs you should discuss with your doctor.

I do not have any personal experience with what you describe - other than I have what I call "troublemares"  most nights, and these do not cause any heart "flutter" feelings.  A truly threatening/scary nightmare likely would.