What Causes Low Pulse Rate And Blood Pressure With Dizziness?

I have heart arritha mea and my blood pressure goes down to 94/55 and sometimes the pulse goes down to mid 40-50. I am feeling extremely low in energy, sometimes a little dizzy. I am taking Metoprolol 25 mg.( 1/2 tablet in morning and 1/2 tablet in the evening after meals) and also Xarelto 15 mg. in the evening after meals. Angiography was performed in mid April, 2015 and all the arteries were found quite clear from my heart bypass surgery in 2005. I need the response from only a cardiology surgeon or electro cardiac surgeon.