Pectus Excavatum, Low EF, Aorta Stenosis

I am a 50 year old female, normal weight, good blood count and in great health. I had Hodgkins disease in 1976 with radiation to the chest (no chemo) with total remission for 33 years. My problem is I suffer from anxiety and when in a stressful situation a few weeks ago my heart started beating hard and I had palpitations which isn't new, but it continued for a couple of weeks.  This brought me to a cardiologist.  He did blood work (normal), EKG and echocardio gram.  The echho showed 50% EF and now they want to put me on Lisinopril and Metorprolol.  The echo also showed moderate Aortic stenosis which he said they'd monitor yearly, but no treatment now. The EKG was inconclusive so they have ordered a nuclear stress test.  I think this could be a misdiagnosis because I have severe pectus excavatum.  I told the cariologist about the pectus excavatum, but he did not look at my chest, so I don't think he realizes the severity of this nor did he take this into account with the interpretation of the tests.  I've read pectus excavatum can decrease the EF and make it difficult to interpreet echocardiograms.  Is my EF 50% abnormally low for someone with pectus excavatum?  Do you think I need a second opinion before starting medicines?  Do I even need meds?  Do you think I should see a cardio thoracic surgeon  or someone who has experience with pectus excavatum and heart problems instead of a cardiologist?  If so, how do I find such doctor?