bandmom,
Sorry to hear of your ordeals.
Your question is intriguing. The low diffusion capacity and newly diagnosed asthma are suggestive of a problem with the left
ventricleUltrasound, normal fetus - ventricles of brain
Ultrasound, normal fetus- ventricles of brain. Another cause of a low diffusion capacity is
fibrosisCystic fibrosis
Cystic fibrosis - resources
Neonatal cystic fibrosis screening of the lung tissue.
This constellation of problems needs careful evaluation. You haven't given your age, but I am suspicious of the diagnosis of asthma.
"Acham's razor" is a rule of thumb in medicine. The rule is that given two explanations for a group of findings or symptoms, the explanation that is the simplest is usually correct. I would try to find a unifying diagnosis for why you have a low diffusion capacity, right atrial enlargement, and new-onset asthma.
Hope that helps.