Hello , because a bubble test was done at age of 51 years , it's mostly patent foramen oval.
Before I start I would like to reassure you that it's nothing be be stressed about and completely benign entity.
It's present it's 1 in 4 adults.
Now , per say it doesn't cause
low BP , and if you have Blood pressure on lower side , why have you been put on
blood pressure medication as they are for people who have higher blood pressure. Also many blood pressure medication if are given at higher dosage can cause what Is called as
orthostatic hypotension, it means there is fall in blood pressure when you suddenly stand up or sit from sleeping position , which may be the reason of passing out episode.
Do evaluate you noodles pressure medicines and maintain Good hydration.
Lastly the hole in heart can cause sometimes transient is chemical attacks of brain which may cause passing out like clinical scenario , so do rule out the same .
Hoping I could help resolve your concern.
Regards Dr Priyank Mody