My middle daughter has a heart murmur and we did not find out unitl last year. She is now 7. She is active and healthy. When they found it I had taken my 2 oldest for a ck up with the cardiologist becausemy youngest daughter was born with heart defects and so was my husband. After hearing about all these kids in athletics having problems with undetected heart defects.. I took them in. The oldest was fine and the middle one does have the murmur. They did a EKG and a echo. The EKG was what detected the murmur and they followed it up right then with the echo. She was fine. They will monitor her every couple of years. They said some kids outgrow it, others live just fine with it. My yongest who had corrective surgery at 5 days old still has a murmur but she is a healthy 6 year old and the cardiologist said that if you did not know she had 3 heart defects when she was born...you would never know..So I am sure that you are scared and worried. I have been there. I am sure that in the end your baby will be fine. Technology today is wonderful.
I'm sorry you've received such news. And then all the waiting for more tests and results is stressful for you. I think when they do more tests you'll have a better picture of what's going on in there. All three of my kids had murmurs when they were young (they called them functional heart murmurs) but they're fine now. I'm not sure how accurate a diagnosis of LVH is from a simple EKG. Perhaps someone else knows the accuracy rate. In any case I think it will be a matter of wait and see. When is the echo scheduled? Is she doing fine otherwise - active, eating well, good color? Hope everything turns out well for you both.