My mother blacked out and fell a couple years ago, ending up in the e.r. Because of a history of heart problems, the dr. ran all kinds of heart tests, but nothing showed. Finally, he decided to do a urine test and then he was going to send her home with no answers. Yup, she had a UTI, correct meds were then given. It was scary though. She was 81 at the time, and we children were concerned about strokes, etc. When I checked on the internet, passing out was listed as a symptom. And my mom is like so many others of that generation, she doesn't tell the dr. everything, or glosses over it.