I've wondered the same thing. Since the ACGME only requires 12 months of your fellowship be spent in the ICU, could you spend the next 12 months doing ultrasound? I've also wondered if you could use the second year to study echocardiography and take the echo boards instead of RDCS. Since I'm only an EM-1, I've got a while to go before investigating it more.
How you found out anything since you first posted this message? What do CCM fellows do with their second year?