In medicine pulmonary artery catheterization (PAC) is the insertion of a catheter into a pulmonary artery. Its purpose is diagnostic; it is used to detect heart failure or sepsis, monitor therapy, and evaluate the effects of drugs. The pulmonary artery catheter allows direct, simultaneous measurement of pressures in the right atrium, right ventricle, pulmonary artery, and the filling pressure ("wedge" pressure) of the left atrium.

The pulmonary artery catheter is frequently referred to as a Swan-Ganz catheter, in honor of its inventors Jeremy Swan and William Ganz, from Cedars-Sinai Medical Center. The idea for a sail or balloon tip modification of Ronald Bradley's simple portex tubing method came about from Dr Swan's observation from the Santa Monica shore of sail boats on the water on a relatively calm day. Boats with conventional slot sails were still; one with a spinnaker was able to make reasonable headway. The concept of using thermodilution to measure cardiac output was originally the idea of Arnost Fronek MD, PhD of the Cardiovascular Institute in Prague. As a former colleague of Fronek, Ganz added the thermistor modification after Swan showed him the initial balloon design, which was fabricated by Edwards Laboratories, which had previously contracted with Swan as a consultant.