Long QT syndrome?

The cardiologist just resently told me i have "borderline" Long QT syndrome(i am 24). I only got checked cause my sister's heart stopped (she literally died and they brought her back with shock pannels) and was diagnosed, and at 25 she wears a pacemaker.

Well im worried about being "borderline". Im 25 weeks pregnant and worried about dealing with this during pregnancy. Long QT can induce siezures, shortness of breath, stop your heart, ect.

Ive always been super short of breath(i always thought it was from having large breasts) but now being pregnant its worse.

Had anyone dealt with Long QT while pregnant (or just Long Qt in general)?