A case of atypical respiratory distress

What would you have done with this presentation?
Young woman chemo
Monoclonal antibody therapies for metastatic breast cancer have improved.

Tracey is a 33-year-old lawyer relocated from NSW, who presents with a six-week history of increasing breathlessness on exertion.

She reports two fainting episodes while doing simple house chores, neither of which was associated with chest pain, seizures or palpitations.