I was finally diagnosed with Prinzmetal angina after 21 years in 2019. this followed several ambulance rides over the years.
The frequency of the episodes had increased to around 5 a week, sometimes 3 in a single 24 hours.
One day I sat down in front of my computer and just looked at the information. Then it hit me! Prinzmetal/unstable call it what you will, happens mainly at night between midnight and 8 am. Right. So what's different about those 8 hours and the other 16 hours of the day?
YOU DON'T EAT!! you're asleep....that is until you're woken up feeling you're in a vice. Pain in chest, back, arm/s neck ,jaw.....
So I decided to have a bowl of porridge about 2 hours before bedtime each night. I went 3 weeks without an episode! WOW.
Then I tried eating a breakfast bar instead, I went 8 months without an episode. I had a stressful time when I lost my younger son so I did have another episode, but much reduced in pain. It's now a rare thing to have an episode, though sometimes first thing in the morning before breakfast I might have a twinge start so I have a biscuit and that works. I very rarely have a full blown episode, if I do there's usually some stress at the time.
I think it points to low blood sugar.
I hope my experience will be a help to someone. Best wishes and good health to all.