I've Been Diagnosed With A 25% EF, What Is My

I've been diagnosed with a 25% EF, what is my survival rate, I'm a 68 years old FEMALE, 5'2 and weight 225, my weak heart could have been caused from some of the chemotherapy medication from 5 years ago, what could be done to improve the EF beside getting to a healthy weight and be active, also I've been on Metoprolol 25Mg and Valsartar 80Mg once daily for the passed 18 months. THE METOPROLOL, was upgraded to 50mg for the passed 2 weeks due to the facts that my EF went down to 25% from 40%... Does my conditions stands as a treatable condition by being at a healthier weight and excercise and Meds or is it a progressively fatal condition regardless of a healthier weight and medication...my doctor is not to clear on that with me or maybe he just chooses not to tell me... My CARDIOLOGIST has also suggested the possibility of a DEFIBRILLATOR , but he does not think that I'm in need as of yet....Please I would like to GET A SECOND OPINION and to know my survival rate and what else to improve the EF..... Thank you...GIGI