Editing Third-degree atrioventricular block (section)

==Treatment==
[[Atropine]] is often used as a first line treatment of a third-degree heart block in the presence of a narrow QRS which indicates a nodal block, but, may have little to no effect in an infra-nodal block.<ref>{{Cite book|title=Tintinalli's emergency medicine : a comprehensive study guide|others=Tintinalli, Judith E.; Stapczynski, J. Stephan; Ma, O. John; Yealy, Donald M.; Meckler, Garth D.; Cline, David|isbn=9780071794763|edition=  8th |location=New York|page=123|oclc=915775025|date = 2015}}</ref> Atropine works by reducing [[Vagus nerve|vagal]] stimulation through the AV node but will not be effective in those who have had a previous heart transplant.<ref>{{Cite |date=2018-07-05|title=Third-Degree Atrioventricular Block (Complete Heart Block) Treatment & Management: Approach Considerations, Initial Management Considerations, Atropine and Transcutaneous/Transvenous Pacing|url=https://emedicine.medscape.com/article/162007-treatment#d8}}</ref> Other drugs may be utilized such as [[Epinephrine (medication)|epinephrine]] or [[dopamine]] which have positive [[chronotropic]] effects and may increase the heart rate.<ref name=":1">{{Cite book |title=Oxford textbook of critical care |others=Webb, Andrew Roy;  Angus, Derek C.; Finfer, Simon; Gattinoni, Luciano; Singer, Mervyn |isbn=9780199600830 |edition=2nd |location=Oxford |pages=730–735 |oclc=954059445 |date=2016}}</ref> Treatment in emergency situations can involve electrical [[transcutaneous pacing]] in those who are acutely hemodynamically unstable and can be used regardless of the persons level of consciousness.<ref name=":0">{{Cite book|title=Rosen's emergency medicine : concepts and clinical practice|others=Walls, Ron M.; Hockberger, Robert S.;  Gausche-Hill, Marianne|isbn=9780323390163|edition=9th |location=Philadelphia|pages=959|oclc=989157341|date=2017}}</ref> Sedative agents such as a [[benzodiazepine]] or [[opiate]] may be used in conjunction with transcutaneous pacing to reduce the pain caused by the intervention.<ref name=":1" /><ref name=":0" />

In cases of suspected [[Beta blocker|beta-blocker]] overdose, the heart-block may be treated with pharmacological agents to reverse the underlying cause with the use of [[glucagon]]. In the case of a [[calcium channel blocker]] overdose treated with [[calcium chloride]] and [[digitalis]] toxicity may be treated with the [[digoxin immune Fab]].<ref name="BMJ15">{{cite web|title=Atrioventricular block, Treatment Options|url=http://bestpractice.bmj.com/best-practice/monograph/728/treatment/details.html|website=BMJ Best Practice|publisher=British Medical Journal| access-date=25 August 2015}}</ref>

Third-degree AV block can be treated more permanently with the use of a dual-chamber [[artificial pacemaker]].<ref>{{cite journal|last1=Dretzke|first1=J.|title=Compared to single-chamber ventricular pacemakers, dual-chamber pacemakers may reduce the incidence of complications in people with sick sinus syndrome and atrioventricular block|url=http://www.cochrane.org/CD003710/VASC_compared-to-single-chamber-ventricular-pacemakers-dual-chamber-pacemakers-may-reduce-the-incidence-of-complications-in-people-with-sick-sinus-syndrome-and-atrioventricular-block|journal=The Cochrane Database of Systematic Reviews|year=2004 |volume=2004 |issue=2 |pages=CD003710 |doi=10.1002/14651858.CD003710.pub2 |pmid=15106214 |pmc=8095057 |access-date=25 August 2015|display-authors=etal}}</ref>  This type of device typically listens for a pulse from the SA node via lead in the right atrium and sends a pulse via a lead to the right ventricle at an appropriate delay, driving both the right and left ventricles.  Pacemakers in this role are usually programmed to enforce a minimum heart rate and to record instances of [[atrial flutter]] and [[atrial fibrillation]], two common secondary conditions that can accompany third-degree AV block.  Since pacemaker correction of the third-degree block requires full-time pacing of the ventricles, a potential side effect is [[pacemaker syndrome]], and may necessitate the use of a [[Artificial cardiac pacemaker#Biventricular pacing|biventricular pacemaker]], which has an additional 3rd lead placed in a vein in the left ventricle, providing more coordinated pacing of both ventricles.{{cn|date=February 2021}}

The 2005 Joint European Resuscitation and Resuscitation Council (UK) guidelines<ref>{{cite web|title=Peri-arrest arrhythmias|url=https://www.resus.org.uk/EasySiteWeb/GatewayLink.aspx?alId=808|website=Resuscitation guidelines|publisher=Resuscitation Council UK|access-date=25 August 2015}}</ref> state that atropine is the first-line treatment especially if there were any adverse signs, namely: 1) heart rate < 40 bpm, 2) systolic blood pressure < 100&nbsp;mm Hg, 3) signs of heart failure, and 4) ventricular arrhythmias requiring suppression. If these fail to respond to atropine or there is a potential risk of asystole, transvenous pacing is indicated. The risk factors for asystole include 1) previous asystole, 2) complete heart block with wide complexes, and 3) ventricular pause for > 3 seconds. [[Second-degree AV block#Type 2 (Mobitz II/Hay)|Mobitz Type 2 AV block]] is another indication for pacing.

As with other forms of heart block, [[secondary prevention]] may also include medicines to control blood pressure and atrial fibrillation, as well as lifestyle and dietary changes to reduce risk factors associated with [[myocardial infarction|heart attack]] and [[stroke]].

Early treatment of atrioventricular blockade is based on the presence and severity of symptoms and signs associated with ventricular escape rhythm. Hemodynamically unstable patients require immediate medication and in most cases temporary pacing to increase heart rate and cardiac output.

Once the patient is hemodynamically stable, a potentially reversible cause should be evaluated and treated. If no reversible cause is identified, a permanent pacemaker is inserted.{{Citation needed|date=December 2019}} Most stable patients have persistent bradycardia-related symptoms and require identification and treatment of any reversible cause or permanent implantable pacemaker.

Reversible causes of complete AV block should be ruled out before the insertion of a permanent pacemaker, such as drugs that slow heart rate and which induce hyperkalemia.

Complete atrioventricular block in acute myocardial infarction should be treated with temporary pacing and revascularization.<ref name="auto">{{cite web |url= https://www.lecturio.com/concepts/atrioventricular-block/ |title=Atrioventricular Block |website=The Lecturio Medical Concept Library |access-date=3 July 2021}}</ref>
{{Citation needed|date=December 2019}}

Complete atrioventricular block caused by hyperkalemia should be treated to lower serum potassium levels and patients with hypothyroidism should also receive thyroid hormone.<ref name="auto"/>

If there is no reversible cause, the clear treatment of complete atrioventricular block is mostly permanent pacemaker placement.{{Citation needed|date=December 2019}}