What Causes Dizzy Spells While Standing?

I am a 53 year old male in good health. I smoke, and I had two heart attacks brought on from stress. I have excellent blood pressure and very low cholesterol. For the past six months, I have been having dizzy spells. If they happen when I am standing, I fall to the left. If I am sitting, things just look like they're moving, or it's hard to focus. I recently had a brain scan done, and everything looks fine, except they notated I have microvascular chronic ischemic disease. I am waiting for my neurologist to call me today. I looked this condition up, and it says that this can be mini strokes. I am not obsessing about this, but something is causing these dizzy spells that have been happening almost daily since last August. Any advice? Thank you