Transient 2:1 atrioventricular block following anaphylactic reaction to low-ionic strength computed tomography contrast agent.

The present report describes the case of an elderly woman who was admitted to the hospital with sepsis and subsequently developed a transient 2:1 atrioventricular block following administration of a low-ionic strength contrast agent for computed tomography. The block resolved after approximately 24 h and did not require a temporary pacemaker. The case identifies an unusual consequence following an anaphylactic reaction to a low-ionic strength computed tomography contrast agent and suggests the potential role of histamine release as a mechanism underlying this reaction.