Annular Fat Pad in Rt Ventricle/ EF: 45-50%

I'm not quite sure where to go with this question, so I'm trying my luck here, as I'm not getting clear answers from my Dr. I gave birth Aug 2010; during my pregnancy, I had very pronounced palpitations that were driving me up a wall. I've been dealing with palpitations on and off for the past 10-12 years, but it got particularly pronounced in my second pregnancy. I'm 30 years old. I also have asthma, and occasionally dealt with shortness of breath that didn't seem to feel like an asthma attack, and certainly wasn't fixed by using my inhaler. I wasn't quite sure if this was related to a panic attack or what, but after awhile, it'd go away. It just felt like no matter how much air I took in, I couldn't get enough.
During the 3rd trimester, I got a stress echo with ultrasound done, and was told I had a "trival valve leakage in my tricuspid valve" and something that was reminiscient of an "annular fat pad" in my ventricle. I was told to get a repeat echo after I give birth, and not to really worry about it. EF was 50-55% then.
I recently repeated that echo - got it done about 2 weeks ago. My EF is now 45-50%. Valve supposedly is not leaking, and supposedly, the "annular fat pad" is no longer there? Still have palpitations and occasional episodes of breath shortness. Dr. wants a repeat of an echo in 3 months, instead of 1 year, after getting the results from the cardiologist who did the echo, but otherwise appears unconcerned.

First off, what does an EF of 45-50% mean to me?

Secondly, should I be concerned of an "annular fat pad" in my ventricle, as well as the fact that it is no longer there? I've not been able to find any information as to how a fat pad gets in your heart, or if there is any dangers of them disappearing.

Supposedly, there were no other remarkable findings on my echo.

Please help.