Welcome to HealingWell. Congratulations - 12 years and all is well, that is truly great for you.
I am going to link you to Cleveland Clinic as they are considered number one by many when it comes to heart disease. The site is huge so get your shovel ready and dig for info that will help you with your concerns.
After reading do post any specific questions you may have.
My personal experience was from my 79 year old sister's sister's heart surgery for mitral valve failure. The cardiologist was good but I wish I could have sent her to Cleveland Clinic but she was not well enough.
I look forward to getting to know you better.