At my last appointment with PM, I mentioned that my meds were causing some pretty uncomfortable issues. Though this is a discussion I didn't really want to have with her, it became necessary because of how bad it was. She prescribed "Amitiza" to use daily. It's not stimulant laxative. But, you must take it twice a day for it to be effective. I've been on it for a week now and I must say it helps considerably without having any cramping or other nasty side effects.
There is another med available now called "Relistor" which is an injection that is supposed to help, but it hasn't been studied for anyone who has heart issues.
Several Epidurals, L4-S1 360 ALIF, Numerous Facet Joint Injections, RFA x2