LAUSR

Influenza causes cardiac and pulmonary complications that can lead to death. Its effect on the conduction system, first described a century ago, has long been thought to be fairly benign. We report 2 cases of high-grade atrioventricular block associated with acute influenza infection. Both patients-a 50-year-old woman with no history of cardiac disease or conduction abnormalities and a 20-year-old man with a history of complex congenital heart disease and conduction abnormalities-received a permanent pacemaker. In the first case, pacemaker interrogation at 4 months revealed persistent atrioventricular block. In the second case, pacemaker interrogation at 3 months suggested resolution. Whether such influenza-associated changes are transient or permanent remains unknown. We recommend keeping a careful watch on influenza patients with cardiac rhythm abnormalities and monitoring them closely to see if the problem resolves.