As none of us are doctors and your LVEF abbreviation (I had to look that up), your case is a little more complicated. Involving "ejection fraction" or pumping of the blood from your heart, that number does appear to be low to me as I have also had a triple bypass as my doc introduced me to that reading...I am lucky at 60. Your oncologist should be up speed on this however, I would probably get a second opinion for fresh eyes and peace of mind if you have any doubts.
One other observation. Is he recommending chemo alone or with a cystectomy? Chemo is usually done along with that procedure after the chemo is finished on stage 2 (T2) or higher tumors.
Please keep posting as you go. Others will learn from this.