Mild pulmonary hypertension and PFT's

I have been diagnosed with mild pulmonary hypertension (44) by echocardiogram.  I have been having tightness in chest, shoulders, and neck.  Was hospitalized with possible MI, but that was ruled out. Stress test was basically normal, but unable to exercise to required level due to leg pain and shortness of breath.  Have had heart cath that showed some elevated pressures, no blockage, and some luminal changes. Today I had PFT's.  The technician said the pre-nebulizer treatment test looked on the low normal side, but she felt okay.  However, after the bronchodialators, my function dropped to 1/2 of with the dialators.  What would cause that?

[National Jewish]

Pulmonary function testing requires that you give your best effort.  Fatigue from the testing that you had done before taking the bronchodilator in the nebulizer may have kept you from giving your best effort during the testing that followed.
Another cause could be a paradoxical response to the bronchodilator.  After taking the bronchodilator the airways of the lungs tighten rather than opening as they should.  If this is the cause repeating the test with a different bronchodilator should show an opening of the airways of the lungs.