Attention! One of the Causes of Second-Degree Mobitz Type 1 AV Block: Pheniramine Maleate

Abstract

Atrioventricular (AV) blockade is the loss of function of the pathways that provide electrical conduction between the sinoatrial node (SA node) and the atrioventricular node (AV node). It is rated according to the level of distortion in the transmission. First-degree and second-degree Mobitz type 1 blocks are usually benign, but hemodynamic instability in second-degree Mobitz type 2 blocks and third-degree AV blocks can begin suddenly and unexpectedly, causing syncope or sudden cardiac death. Myocarditis, inferior myocardial infarction (MI), previous heart operation, and treatment with drugs such as beta-blockers, calcium channel blockers, digoxin and amiodarone can cause AV blockade. However, in the patient described in our article, an AV block developed after the injection of pheniramine maleate, an antihistamine we used to treat urticaria. Pheniramine maleate is a first-generation, stable, potent, sedative, antihistamine from an alkylamine group. The cardiac side effects of pheniramine maleate are tachycardia and arrhythmias.