Hello,
I am sorry to hear about your daughters health problems. What appears to be conflicting information about your daughters health can be frustrating.
The interpretation of imaging studies is dependent on the quality of information given. For example, if there is any movement by the patient during an MRI the data can be difficult to interpret and if the rib spaces are too close, echos can be difficult to interpret. This is a long winded way of saying that I wouldn't focus on the number, I would focus on the concept. your daughter has a decreased ejection fraction and has mitral regurg. The ejection fraction is somewhere between 35-45%.
Regarding the possible surgery, it is usually best to be in a high volume surgery center where they tend to see a variety of cases.
I hope this answers some of your questions. We wish your daughter and your family well. Thanks for posting.