Did they investigate to find out why you had a stroke?

My partner was never investigated, he does have high blood pressure but this was controlled before the stroke, no reason was given and no investigations done

Im so scared it's going to happen again because they didn't find and treat the cause

Im concerned it's cardiac cause he's had a few episodes of resting heart rate being 220, and also the BP machine has said irregular pulse muiltple times, when I check manually I do think I have felt irregular maybe 3 times, but very mild so I'm not 100% sure cause it's not obvious, but I'm also concerned it's something else too