PES D for NS when I already went for medical checkup

So I went for the normal checkup everyone went, and then they say my heart kinda weird, might have irregular heartbeat, so I got asked to go to the NHS to go checkup.

So ofc, I went there for a checkup, 3 months later I checked, got PES D.

So is there anything I should expect? (like the start of my NS different from others?)

Cause my weight is avg, and my fitness lvl is above avg too.