Health Insurance claims Pre-existing for Long Q-T!

I am seeking advice from anyone out in this community on any experience they might have had with their insurance company refusing to pay for treatment of Long Q-T. My situation is that my daughter was seen at the cardiac clinic at the children’s hospital in our area four years ago from fainting while running at school.
She underwent extensive tests and was cleared of having any heart problems then, 2003. Subsequently, in January 2007 I received a call from the EP Specialty Nurse at this clinic asking me to bring my daughter back in to be reevaluated by the new and current EP Cardiologist. They looked at her file and informed me of two new tests that are available now, that wasn’t then, and they would like to test my daughter. One was the EP Study the other Genetic testing. In January I took her to have the EP Study which came out borderline and the doctor ordered genetic testing that came back positive for Type II Long Q-T. This was the first I had heard of this disorder. My daughter was put on beta-blockers while we waited for her genetic results. Before the results came back she was diagnoses as P-Long Q-T, (possible) in January. Only after her genetic test came back in April did she have a positive diagnosis. She was implanted with an ICD in April. The issue I have with my health insurance, Humana, is that I just changed my insurance last year the 31st of December 2006. I mentioned to the underwriter of her check up at the hospital a few years earlier and that she was cleared of having a cardiac problem and that we were told that she probably fell because of not eating a proper breakfast and we left it at that for 3 years, until I got a call from the cardiac clinic in January 2007. Now the issue is that the insurance company is stating that the Long Q-T is pre-existing and that they won’t pay for her treatment because of her previous visit to the clinic four years earlier. However, we were never given a diagnosis and were told she had no problems at that time. In addition and only to confuse me more, Humana, our insurance company paid for the January 2007 EP Study that diagnosis her for P-Long Q-T and part of the payment for the genetic test, in addition they paid for part of her medical visits to the cardiac clinic in March, her post-op in May and July, BUT NOT in April for the treatment and implantation of her ICD, a whopping $62,000!!! I am furious, how can they or why would they pay for the diagnosis and post-op visits but not the surgery? As a policy holder my question is that if Long- Q-T is considered a pre-existing condition then it should be all or nothing in the form of payment on her case. I would appreciate any comments or thoughts anyone might have or similar experiences. Of course I have filed a Grievance and Appeal document and will wait out the process. I am looking for any legal rights we have. If the condition was not confirmed until April and suspected in January then surely this does not constitute pre-existing right?