Thsi is urgent please help?

My partner of twenty two years of age, has a mother who two year sago had open heart surgery. She has for th epast week felt like death, weak sore..she has just been taken to hospital shes about 48 ish...shes had blood tests nothing found...my partner is coming home and i have to tell him....does anyone know the life expectancy after open heart surgery and what could be going on?