Only thing I can suggest is review the CHF stuff and remember that you will learn a lot on the job. Don't be afraid to ask questions, better to admit that you don't know than to make a big mistake. Is this a "cardiac unit" or just for CHF. P.S. they thought you could do the job so they hired you, right? so keep your confidence and try not to let the patient see you nervous or unsure, because the patient will feel the same way about you as their nurse.