I work on a hematology-oncology floor--also at a large, teaching, magnet hospital. On my unit we treat leukemia, lymphoma, and multiple myloma patients. We also re-admit BMT patients who return with illness 6+ months after transplant. The BMT floor is considered critical care. They do hire new grads in the residency program.
Hematology patients in general are very ill/acute. You'll give a *lot* of chemo and hang a TON of blood products.
As for your question about transitioning to cardiac ICU, I can't comment on that. Oncology and cardiology are too distinct specialties. While oncology patients can have cardiac complications from chemo, most have limited cardiac history (I see a-fib most often on my floor). Patients receive a cardiac work-up including an echo prior to starting therapy to establish a baseline, and ensure they are healthy enough to undergo chemo/transplant.
Finally, in regards to your question about preparing, most information will make more sense once you are actually in the residency program and have a patients to put a "face" and context onto everything you are studying. I highly suggest that you keep a small note-pad to jot questions down in. Once you have down time look up the chemo regimens, malignancy sub-type, therapies, etc. that you had questions about on a respected website. I like Latest Medical News, Clinical Trials, Guidelines – Today on Medscape
(it's free) and Evidence-Based Clinical Decision Support at the Point of Care | UpToDate
(free if your hospital subscribes to it like mine does). Do learn the basics of neutropenic precautions, thrombocytopenic precautions, and lab values you can expect to see in your first 1-2 weeks of orientation. After that focus on the most common hematology emergencies (neutropenic fever, tumor lysis syndrome, bleeding emergencies, and superior vena cava syndrome).
You may also find the following websites helpful as places to start: ONS | Oncology Nursing Society
They have a wealth of knowledge for oncology nurses. There are monthly meetings in almost every major city as well where you can network and learn. They also offer online classes, but can be a bit costly
I also recommend looking over Leukemia & Lymphoma Society | Donate Today!
and Chemotherapy | American Cancer Society
Best of luck. Hematology/oncology is truly a cutting edge field where we are discovering new treatments and saving lives. I'm passionate about our patients!