TNCC is easy as has been previously stated. Getting your CEN on the other hand is no joke..
study.. study..study.. learn everything you can about cardiac stuff.. know your EKG stuff inside and out.
you need to be able to determine the difference between a 1st,2nd,or 3rd degree block easily..
i know that might sound easy.. but trust me.. its not always that easy...
wish you the best of luck!!..
like i said before.. if you are going for your CEN.. get the books... study the material.. dedicate yourself and you will do fine...~~