What will high blood pressure do if left untreated?

Kill you: It's slow but steady. The small arteries are progressively damaged. Your kidneys will malfunction. Your brain will fail from lack of good microcirculation & the dementia is likely to be mistaken for alzheimer's. You'll eventually have the muscle in your heart fail, and your last few months will feel like you're running a marathon just to walk to the bathroom.

It may cause heart: Enlargement, clogging of arteries, heart failure, heart attack, stroke & death. Best wishes!