What kind of blood infection can lead to cardiac arrest?

i have been to the doctors and has x-rays but no blood drawn and they say they dont have a reason to..but i am worried i have an infection in my blood stream that will lead to a cardiac arrest for personal reasons..it has been about 7months i been having this feeling. I have had bronchitis and congestion on my chest wall 3x since anyone have any ideas what and how to go about getting blood work for this worriness?