beta blockers resulted in severe bradycardia at 40-50 bpm while at work and 20-30 while sleeping, pacemaker in 08 is keeping hb at 70 approx 65-70% of time, still tired and/or lightheaded most of the time, sometimes racing at 110+ while sitting

& short of breath, ejection fraction has dropped from 71 in 11-07 to 55 in 9-09, other tests show okay, what should I expect next? Tired of feeling crummy, can't seem to find resolution... Seem to be getting worse again. Dad had 3 HA and died with 3rd at 54. Any ideas? Dr seems unconcerned, and I don't know what to do anymore. Is there any way to know if beta blocker is going to eventually fix this or make me worse?