My blood pressure has always been a little low, never high, and i'm only 26yo. so what could cause diastolic dysfunction?

Causes of DD: Studies show up to 40% of people with CHF have preserved systolic function. Hypertension is a common cause of diastolic dysfunction there are several other causes of DD that affect cardiac compliance including cardiac ischemia, obesity, NSAIDs, pericardial disease, myocardial disease, endomyocardial diseases, aortic stenosis etc. Good to find this early, find cause w/cardiology please & good luck

Unusual 4 u: To have diastolic dysfunction if this is the ONLY echo abnormality (you already stated ur bp is normal). There is no obvious cause. So, u should discuss this with the doctor who ordered the echo (Y was the echo ordered?). I wud recomend keeping trak of ur bp, f/u with ur doc, & repeat echo in 3-6 mos. Good luck.