Complete heart block following anaphylactic reaction to computed tomography contrast agent: A case report.

A complete heart block (CHB) entails the total loss of atrioventricular conduction and the failure to transmit any supraventricular impulses to the ventricles. To date, there have been no reports of CHB following the injection of intravenous contrast dye for computerized tomography. This case study details a patient who experienced a CHB and a syncopal episode after receiving intravenous contrast for a chest computed tomography (CT) scan. The patient was treated successfully for the anaphylactic reaction with steroids and intravenous fluid, and the heart rate improved with atropine and transcutaneous pacing. Contrast agents can affect cardiac conduction and endothelial integrity through their ionic strength, osmolality, and the release of histamine. These factors, combined with localized ischemia and adenosine release, may disrupt ion flow, potentially leading to transient or permanent atrioventricular block. Anaphylactic reactions to CT contrast agents can lead to life-threatening cardiovascular complications, as exemplified in this case. Timely recognition and management of anaphylaxis, along with close cardiac monitoring, are crucial in such situations. Clinicians should be vigilant regarding the potential for severe cardiac manifestations in susceptible patients experiencing contrast-induced anaphylactic reactions, and they should take appropriate measures to ensure optimal care and recovery.