duel pacemaker for sick sinus syndrome with EF of 50

I am a female who was DX. with Sick Sinus Syndrome at age 52 and had a Duel Pacer inplanted.  I am now 55 and using the pacer 40% of the time. and have Atril fib with a rapid response 5% of the time.  In the last year I'm having more SOB with exertion.  My last Echo, and medicated stress test show my EF is between 45-50.  This is down from normal 65 last year.  My Cardiologist said this is normal and not to worry about it.   Does SSS cause a decrease in EF?  I've been on  a beta blocker Toprol XL 100 mg.  for the A-Fib for 3 years.  I just feel the Dr. is ignoring my symptoms SOB, fatigue, pedal edema, and concerns.  I've a non smoker, non drinker, and  (used to be a frequent walker).  before I had started to have these problems again.  Am I just looking for trouble or am I right to be concerned?

[Jerry_NJ]

I do not have any experience (yet, thankfully) with a pacemaker, but I do suffer from permanent AFib and suffer from a similar set of symptoms.

The Toprol can (likely does) contribute to your SOB and other tiredness-like symptoms, but the lower EF may also contribute.  My last EF measure a couple of years back was 60% best I can recall, and I had the same symptoms then, due mostly to the AFib induced heat inefficiencies, I think...I too don't get a lot of sympathy from my cardiologist (or the EP I had for consultations)...as my AFib symptoms are limited to exercise induced tiredness they seem unconcerned.

I am a senior and now on Medicare as my primary and those low payment rates may have contributed to the lessening of interest by my doctors (I was always covered by insurance, but I think before age 65 my med insurance negotiated rates were higher than the Medicare rates), I can hardly wait for the planned full take-over by the federal government here in the USA, when that happens I'll probably not be able to even get an appointment.