The posters at Daytime Dish are discussing a rumor. Supposedly KM’s mom tweeted then deleted that Sam does find out she is a match and comes through surgery successfully after donating. In recovery, someone enters her room and injects digitalis and she dies. It’s Cyrus. The reason being discussed is to free Dante to reunite with Lulu as Cyrus feels guilty for being responsible for Lulu’s coma. I don't believe that. I really think Sam is injured somehow, brain dead and then Lulu gets her liver. They are not about to pull an Anthony Zacarra with Cyrus. This would come out and destroy any progress Cyrus has made with Laura--which is very important to him. I also think that Lulu will remember Cyrus visiting/talking to her and thus, forgive him for the bomb. It's a fact that coma patients can still hear and he sat with her often.
ETA: Digitalis is used to treat congestive heart failure (CHF) and heart rhythm problems (atrial arrhythmias). Digitalis can increase blood flow throughout your body and reduce swelling in your hands and ankles.