Complete heart block during central venous catheter placement in a patient with pre-existing left bundle branch block.

Heart block and arrhythmia are complications of pulmonary artery and cardiac catheterization. Injury to the conducting system of the heart often involves the right bundle causing right bundle branch block (RBBB). If patients already have left bundle branch block (LBBB), complete heart block (CHB) may result. After trauma, impairment of the right bundle is usually transient with recovery in hours, but complete heart block can lead to symptoms requiring invasive treatment. Similar complications are rare with insertion of central venous catheters, as they should not enter the heart. Injury to the right bundle during central venous catheter insertion can be by trauma from the guide wire or from the catheter itself. The function of the AV node and bundle of His in these patients has not been studied before. We report a patient with LBBB who developed CHB during insertion of a central venous cannula. Conduction through the AV node and His-Purkinje system was intact, showing that the transient RBBB was caused by traumatic injury rather than by other disease of the conduction system.