21yo has had sob, ha, tachycardia for 4 months.. tachy is induced with minimal exercision and his bp goes to 190's. sat% is 97, normal pft's, sed rate neg, crp neg, d dimer neg, cxr neg, cbc w diff is normal, tsh normal, ct of head and spine is normal, ua had 1-2 rbc otherwise normal, ige was 86 (mean value is 14--1 standard dev is 41), no fever, no abdominal sxs.
I'm stumped. any ideas