I had an episode of sinus tachycardia almost 2 years ago and was checked out by a cardiologist who could find no problem with my heart and put me on 5mg Bisopropol I have taken since and it was thought stress may have been causal. I had a few more episodes over the following weeks which I was able to quickly control with breathing exercises and since then have had no further episodes. I also take thyroxine. Last night I had some visual disturbance for 5-10 minutes as I drove my car and couldn t read the first letter of car number plates or road names. My doctor is now arranging a hospital check in case it is a TIA and has put me on Aspirin 300mg, Lanzoperole and Simvastatin as a precaution. I had always thought Aspirin shouldn t be taken with Bisopropol as it reduced it s effectiveness. Can you tell me if this is the case? Thank you.