Isolated Progressive Cardiac Conduction Disease By L Brent Mitchell, MD, Libin Cardiovascular Institute of Alberta, University of Calgary Reviewed / Revised Jan 2023 View Patient Education Isolated progressive cardiac conduction disease (PCCD) refers to a group of genetic disorders that involve progressively worsening defects in cardiac conduction, including sinus node dysfunction, varying degrees of atrioventricular (AV) block and / or His-Purkinje system conduction delays or blocks.