Help with pediatric CVT coding...surgeons are placing atrial catheters directly into the atrium (usually through the appendage) at the end of a complex surgical procedure. This can be on the RT or LT and sometimes both RT and LT. The codes the surgeons are submitting for billing are 36555 or 36013. Those do not seem correct. What is the correct way to code for each, RT, LT and for both RT and LT. Please help.

Thank you