Smoking weed after surgery. Heart?

I've smoked weed from being a teenager until I gave up all smoking when it was picked up that I had a heart murmur and had to have a mechanical mitral valve replacement surgery a year ago.I stopped the previous year.I really miss smoking and want to start again,however I can't find any professional advice on the risks.I did not have anything wrong with me such as heart attack or disease and its bit of a mystery why I had the murmur. Is there a greater risk to me versus someone with a "normal" heart? I am on warfarin for the rest of my life and also take a lot of medication for chronic pain from joint hypermobility syndrome and sciatica. Strong pain killers,nerve blockers,thyroid meds,muscle relaxers,beta blockers,alot.