Hello! Thank you for asking on HCM! Regarding your concern, I would explain that her doctor is right, an appropriate medical therapy and careful follow ups are the basis for an optimal approach on heart attack patients. The best guide for judging on life expectation is a comprehensive review of her clinical an medical test data; her overall functional class being the one of the most important indicators. I am not sure about that value 15%: is it left ventricular ejection fraction or just fractional shortening??!! If more than 1-2 months has passed form heart attack, your granny would be eligible for ICD (implantable cardioverter-defibrillator) implantation (if available), and if criteria are met, even an CRT (cardiac resynchronization therapy) implantation would be indicated to improve her cardiac performance. You need to talk to her doctor about these issues. Hope to have been helpful. Greetings! Dr. Iliri