Hello, Very likely her worsening is not related to the use of these drugs together unless she is bleeding. The worsening of her symptoms may be otherwise related to the heart attack itself. Furthermore, Plavix and Eloquis are both medications that may cause bleeding. They can be used together (they work with different mechanisms) but careful monitoring by the doctor is needed to make sure he is not developing hemorrhages (nose bleeds, blood in urine, skin bruises, bleeding gums, black stools, etc). I hope this answers your query. I remain at your disposal in case further medical assistance is needed. Regards, Dr. Antoneta Zotaj General and Family Physician