Beta Blocker differences

After my heart attack and surgery I was put on lopressor and amiodarone for heart irregularities.  Because of the bad side effects of amiodarone I was taken off of that and also my beta blocker got changed.  My beta blocker was changed to metoprolol tartate ..25mg twice a day.  It didn't take long before I noticed that I was having pvc's again (hadn't had while on lopressor and amiodarone) and it has progressed to where it is noticeable every day ......all day long.  Mentioned to my cardiologist who said I should just get used to it.
My question is.............could my generic metoprolol be the reason my pvc's are bad or is it because i'm no longer on amiodarone?   My husband also has irregular heart rate and this week we got him switched back from generic metoprolol succinate to toprol XL and lo and behold he is back in good heart rhythm.  That got me thinking if indeed my problem could be similiar.......one thing that has really upset me is that after my heart attack my EF was at 42% and it has dropped to 30% and again wonder if I need to be on diferent drugs.  My dr thinks that isn't the answer but I'm not sure......
Any thoughts?

[Sandra Y, RPh]

Metoprolol can be used to improve ejection fraction. Other medications such as digoxin or ACE inhibitors (Lisinopril, Enalapril, etc) are also commonly used. It's best to discuss the specifics for your condition with your cardiologist to determine if there's a better medication for you.

[grannyheart]

Perhaps I rambled on too long in my post....what I'm trying to figure out is if my metoprolol works as well as the lopressor (name brand) Considering the fact I've gone down hill with my EF since on the generic I just am wondering if that is one of the reasons. My dr swears all generics are just as good as brand names....guess I'm just looking for answers as to why I'm getting worse...  
Thanks though for your answer and yes will discuss (once again) with my cardio doctor.........

[Sandra Y, RPh]

Generic drugs have the same pharmacological effects as the brand name. People become concerned because generic drugs are often cheaper than the brand-name versions. The FDA (U.S. Food and Drug Administration) requires that generic drugs be as safe and effective as brand-name drugs.

Generic drugs are cheaper because the manufacturers have not had the expenses of developing and marketing a new drug. Without the high costs to bring a new drug to market, other companies can afford to make and sell it for a lower price.