Just started having problems "getting it up" any help?

I have some heart problems and just started taking some new medications(coreg and lisinipril) everyonce in a blue moon i would have a problem getting it up before i started the meds, i would just write it off as a blood pressure problem and not worry about it because i had an understanding partner and it did not happen very often.......but now it has become a problem and it is starting to take a tole on the relationship. Sometimes it just wont go up or it will for only a minute then goes flacid again....any ideas? I cant take viagra because of my heart. I was wondering if anyone had used a pump and good give me some feed back....or if they know of any other solutions.....i am starting to get into a exercise routine which i know will help down the line....but what can i do now?