My dad is an Heart Pateint since last 7-8 years and he has been taking medicines since years. His main problem is short of breathing, fatigue, sweting, enlargement of heart etc etc... But nowdays he is having severe problems. My dad is not getting any relief after taking medicines either so doctor had suggested valve replacement. So my question is Is valve replacement surgory is safe? after surgory my dad will get relief or not? and how long will this surgory works? main question is Is this surgery is safe or any risk is there? and what is EF, my dad's ef is also very low 26% , 3 months back it was 55%..... please guide me in detail if possible...