lisalisa, I spoke to my dh and he basically said (1) he knows nothing about Waldenstroms, only the name of it as it is pretty rare and (2) he thought that if they were suggesting chemo then the docs who are treating him would have more idea and wouldn't be offering it if he couldn't take it. Breathig diffuculites and a pacemaker shouldn't contraindicate chemo, but he will have to take it VERY easy.
But he didn't want to commit himself to saying what the effects could be, not knowing your dad and not being able to see his medical notes and examine him.
I know this sounds like a copout but he really didn't want to give you false information. Both of us wish you all all the best and I'll be checking back to find out how he does. Love, Susan xxx