Heart issues and breathing problems and dealing with dementia

https://connect.mayoclinic.org/comment/696897/
I think my husband should be on oxygen while waiting for results of a heart monitor recording his heart beats. Depending on results, he may get a pacemaker. We don’t know how long it will take to get the results and he is having problems breathing. Two doctors have seen him since his hospital visit and neither one suggests oxygen. He wants the do more, but runs out of breath when he tries, so all he can do is sit in a chair. Can someone relate?