There are a number of Nursing Certifications out there including a few specific to Cardiology. The ones that come to mind for me are: Cardiac Vascular Nursing, (the one I'm considering) Cardiac Medicine Certification (CMC), and Cardiac Surgery Certification (CSC). There are also some for the Critical Care Nurse. As far as societies or associations are concerned, PCNA (Preventative Cardiovascular Nurse Association) and AACVPR (American Association of Cardiac and Pulmonary Rehabilitation) are the only ones I can think of. Two places you can find information are with your employer for the ones they prefer and the internet. Good luck with your search and certification.