Yes, that is certainly correct, most heart attacks do happen in the morning. Why? One of the reasons is that upon awakening we are in some sense dehydrated and our blood "thicker" & is more prone to clot easier. Also morning awakenings can be very anxiety provoking for lots of people which in turn produces stress hormones and, of course, stresses the heart, raises B/P. I always took my 3 blood pressure medications in the morning until I noticed in the evening around 7 or so, I felt stressed and my b/p was up. So I am now taking one before bedtime, the other 2 remaining in the morning. I still need blood pressure control during the day so if I could - would take all of them in the evening. And during the night we could be having difficulty sleeping which will increase B/P or in our sleep have very disturbing dreams which stresses us out. If you are having great calming sleep and this is still happening I would bet dehydration is at work plus an anxiety reaction which gradually decrease as the morning progresses. And for me, just the "thought" my blood pressure is high, stresses me out and I get into a loop which is hard to get out of. I have fear of a stroke, etc. since I am a cardiovascular patient with bad genetics in my family. My Dad developed heart disease at 39. Many factors can be involved. Exam your mental health. I am a big believer in the mind-body connection. It really can not be denied.
Lots of luck to you!