Your question cannot be answered
on-line. Your concerns require a physical exam and review of what your were before surgery and to better appreciate what your current concerns are. If you are really worried and there is an obvious deformity, you should be in contact with your surgeon now so if any maneuvers known to be beneficial could be implemented before you 'heal'.
Revision breast surgery and concerns
I think that with your history it would make sense to be seen in person and preferably by your surgeon. It is difficult to comment without more information and photos at the minimum.
Secondary revision issues
It would not be wise to speculate on your specific issues without a lot more information, and really a personal consultation is important for complex revision issues. When you have already had one revision, and apparently previous heart surgery, detailed analysis and planning is the key to avoiding getting into a cycle of multiple revisions. There are several possibilities: one is that your results really are as good as they can be given the circumstances; another is that revision with an internal bra using material such as Strattice, SERI Scaffold, or GalaFLEX mesh would definitively hold the implants where they need to be; another is perhaps using form-stable implants which are textured and may stay in place better than smooth ones. It may of course be something else.