Cardiolite tomorrow

I'm 27, female, no chemicals except nicotine and no known family history of cardiac issues at all.  I'm scheduled for a Cardiolite stress test and echo tomorrow after spending this afternoon in the ER.  This morning I had very sharp, stabbing chest pain that radiated to my back and off to the side on and off for an hour.  Before that I had a 10-minute long episode of nausea, and about two hours after the chest pain I had about 15 minutes of lightheadedness/dizziness.  I ended up leaving work early due to continuing chest pain and fatigue and called my doctor on the way home.   His nurse suggested that he would want me to go to the ER because of the nausea before the pain and the dizziness/lightheadedness after.  EKG "pretty normal" (?), cardiac bloodwork normal, chest x-ray presumably normal (doctor didn't comment on it).  

Now, I've been diagnosed with SVT (6 years ago while pregnant with my younger son) and mitral valve prolapse (1 leaflet) with mild regurgitation.  I had an echo about 2 months ago that showed the MVP/R plus enlarged atria, mild LVT, trace tricuspid regurgitation, mild pulmonic insufficiency and high pressure in the RV.  Ejection rate normal.  Holter done at the same time showed some PACs and late beats and both bradycardia and tachycardia.  I'm currently taking 100 mg of Toprol XL a day (plus 300 mg ranitidine to control heartburn, which it doesn't do).  I've been having left-sided chest pain (pain scale 1-3) that radiates up to my shoulder and occasionally down my arm nearly every day for the last 2 months but this stabbing pain was a new pain.  I took some ibuprofen before I left for work to make sure it wasn't muscular pain because I was having some neck and back muscle tightness/soreness.  The back/neck pain went away but the chest pain didn't.  Prior EKGs normal except for the episodes of tachycardia.  ECG three months after diagnosis of SVT showed the mitral valve regurgitation but no f/u with cardiologist since delivery.

Family doctors have been handling all this so far (I've moved a lot in the last four years and haven't had insurance for a lot of it) and I finally see a cardio on Wednesday.  What is the Cardiolite test going to actually tell them?  It checks for narrowing of the arteries, damaged tissue, etc.  Is this to just confirm the echo findings, and if so, why are we doing another echo then?   I'm getting equally tired of tests that don't explain anything as I am those that turn up problems.  I'm tired of the chest pain even though I'm taking meds and doing everything I can to ward off the SVT.  Could all of my cardiac problems be related to each other, and are any of them causing my symptoms (chest pain and SVT being the major ones)?

[Sweetwaterguy]

The Cardiolite test will give a good indication of blood flow to your heart.    If the test indicates you have adequate blood flow it tends to rule out blockages.  If the test suggests problems, then further more extensive testing will be indicated.