I forgot to mention the obvious, if you do have raised intracranial pressure, the drug Diamox (acetazolamide) reduces this.
Secondly, I’ve found that a comprehensive multivitamin helps me feel quite a bit better fairly quickly, when my heart’s particularly playing up. I use Boot’s own brand “Multivitamin Effervescent”. I’ve seen the same quick improvement in my elderly aunt, when I gave her one of my grandchildren’s gummy multivitamins, when she was obviously suffering from heart type problems, I don’t know the specifics of how it works, or what element is most useful, I just know it helps.
Worth a try ?