Editing First-degree atrioventricular block (section)

== Causes ==

The most common causes of first-degree heart block are AV nodal disease, enhanced [[vagal tone]] (for example in athletes), [[myocarditis]], acute [[myocardial infarction]] (especially acute inferior MI), [[electrolyte disturbances]] and medication.  The medications that most commonly cause first-degree heart block are those that increase the refractory time of the AV node, thereby slowing AV conduction. These include [[calcium channel blockers]], [[beta-blockers]], [[cardiac glycosides]], and anything that increases cholinergic activity such as [[cholinesterase inhibitor]]s.<ref>{{cite journal |url= https://www.ncbi.nlm.nih.gov/books/NBK448164/| title= First Degree Heart Block | website= National Center for Biotechnology Information, U.S. National Library of Medicine | year= 2023 | pmid= 28846254 |access-date= 3 July 2021 | last1= Oldroyd | first1= S. H. | last2= Quintanilla Rodriguez | first2= B. S. | last3= Makaryus | first3= A. N. }}</ref>