CVICU is your post open hearts (Bypass, valves, aortic grafts, etc). CCU/CICU is still medically managed and minimally invasive pts (think drips, arrhythmias, post-cash STEMIs, balloon pumps, heart failure, etc).
It really depends what you are interested in. Do you like the current pt population on your floor? Go CCU/CICU. If you want to learn a different area of cardiac nursing go to CVICU. Either way, make sure you shadow a RN on each floor.
Also, I would wait for your CCRN until you actually get into an ICU. If you are on a step-down get your PCCN.
I started off on a cardiac step-down like yours. I originally wanted to move on to CICU or CVICU but ultimately Im trying to go in the direction of outpatient or a procedural area.