I Am On 3 Blood Pressure Medicines, Warfarin And Levothyroxine.

I am on 3 blood pressure medicines, warfarin and levothyroxine. I had aortic valve replacement in 2007 'and I rec'd a pacemaker less than a year ago. I am 69 female and still working. my issue is that since the surgery I have become much more forgetful, can't focus on tasks, don't have interest in some of the things I did previously like reading except for short articles and working outside. I can't organize & keep up with things anymore. I don't have as much of a problem at work but it is easier to keep everything on my desk. Are the medicines to blame or the surgery? I haven't asked my dr. but if I was on a heart-lung machine could something have caused my problems?