@mirsy That's an interesting question that I just faced as well. In my case, it was shortness of breath, fatigue and chest pressure with no previously diagnosed heart condition. I have Bronchiectasis but did not seem to have any infection, but the way I felt I was sure there was one lurking.
Then I got Covid and was sent to the ER because of the chest pain. There I was diagnosed with a heart blockage and angina. Medication has me feeling fine right now.

I am glad your husband's doctor is taking this seriously, because it could be either his CHF or an infection. Maybe his pulmonologistncan have the respiratory therapy staff help him get a good sample?