Swan, Harold James Charles (born 1922), and Ganz, William (born 1919), American cardiologists. From the 1960s Swan served as director of cardiology at a Los Angeles medical center and as professor of medicine at the University of California. In 1970 he introduced a catheter with an expandable balloon tip for use in measuring blood pressure in the pulmonary artery. Swan was greatly assisted in the development of the balloon catheter by Ganz. Together Swan and Ganz also developed a multipurpose catheter that incorporates a number of electrodes in its shaft.