The PA catheter and complete heart block

In the dark ages when the word Swan was a verb it was not uncommon for traditional internists in smaller hospitals to Swan patients. I know I did quite a few back in the day. Occasionally, due to trauma to the right septum, the procedure induces a (usually transient) RBBB. If the patient has pre-existing LBBB this of course would cause complete heart block. For that reason I always avoided the procedure in such patients. Now a paper in the Journal of Cardiovascular Electrophysiology suggests a low risk LBBB pattern that carries a low risk of CHB following PA catheterization. The pattern, characterized by an initial R wave amplitude of 1mm or greater in V1, suggests that the LBBB is less than “complete.”