Highlights & Basics
- Atrioventricular (AV) block can be described by degree (based on ECG appearance) or by anatomic level of block.
- The degree of AV block or anatomic level of block does not necessarily correlate with the severity of subsequent symptoms.
- The goals of therapy are to treat symptoms and to prevent syncope and sudden cardiac death due to very slow or absent ventricular rates.
- Patients with advanced AV block (usually type II second-degree, third-degree, or infranodal AV block) of irreversible cause should undergo permanent pacemaker placement.
Quick Reference
History & Exam
Key Factors
Other Factors
Diagnostics Tests
Treatment Options
Definition
Epidemiology
Etiology
Pathophysiology
Images
First-degree AV block
Type I second-degree AV block. This figure demonstrates typical features of the AV Wenckebach, including progressively shortening R-R intervals as the P-R intervals lengthen; the figure also shows grouped beating, which is also typical for AV Wenckebach
Type II second-degree AV block
Third-degree AV block
Third-degree heart block: right bundle-branch block escape
Baseline ECG for a patient with third-degree AV block
2:1 AV block
Tachy-brady syndrome due to sinus node disease. Ventricular rate is slow intermittently, but AV block is not seen
Patient with 2:1 AV block, status post permanent pacemaker placement
Citations
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Tracy CM, Epstein AE, Darbar D, et al. 2012 ACCF/AHA/HRS focused update of the 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology Foundation/American Heart Association task force on practice guidelines. Heart Rhythm. 2012 Oct;9(10):1737-53.[Abstract][Full Text]
Glikson M, Nielsen JC, Kronborg MB, et al; ESC National Cardiac Societies; ESC Scientific Document Group. 2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy. Eur Heart J. 2021 Sep 14;42(35):3427-520.[Abstract][Full Text]
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