Thank you for your question and welcome to EmpowHer. How many times have you fainted or passed out? Is this a common occurance? Do you have a rapid heartbeat?
Unfortunately, you may have to see your physician for a proper diagnosis. Here is a link for information about NCS http://www.dinet.org/NCS/ncs.htm but follow up with your physician is certainly necessary especally since you may have heart issues in your family. I hope this information helps. Keep us posted.