Marino's book is excellent for MICU/SICU rotations/patients, but a CCU rotation will require slightly different focus.
I highly recommend "Manual of Cardiovascular Medicine" edited by Steven P. Marso, Brian P. Griffin, Eric J. Topol, published in 2000 by Lippincott, Williams & Wilkins. $39.95. I bought this book as a 4th year medical student while doing a CCU month at the Mecca of Cardiology, the Cleveland Clinic. Dr. Topol is the chair of Cardiology there and Dr. Griffin is faculty, while Dr. Marso is a former fellow. The book is divided by topics (e.g. Acute Coronary Syndromes, Chronic Ischemic Syndromes, CHF, Valvular Disease, Arrhythmia, Diseases of the Aorta and Pericardium, Adult Congenital Heart Disease, Common Cardiology Consults, Preventive Cards, Non-invasive Assessment, EP, Procedures (percutaneous, of course
) and contributors are all Cards fellows/faculty at the Clinic. While that may imply an institutional slant, the Cleveland Clinic pretty much is a standard-of-care setting place, so that isn't too much of an issue. The book will give you a good overview of things you'll see in the CCU, management & rationale. As you can tell, I highly recommend it.