I think cardiac and critical care are two distinct fellowships. Might check out the gas forum for more info.
Yep- cardiac and critical care are two separate fellowships, but each is one year long, so it's definitely not unheard of for people to do more than one fellowship in anesthesia. Some people even then divide their time as attendings among different areas- for example, doing half of your time in the cardiac ICU and half in the OR doing anesthesia for cardiac surgery. This may be more common in community vs. academic settings (the people who've said they do this have all been working in private practice groups serving community hospitals).