Second degree AV block type II: Difference between revisions
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==Background== | ==Background== | ||
*Significant risk of hemodynamic instability, symptomatic bradycardia, and decompensation into [[Third Degree AV Block]] | [[File:Second degree heart block.png|thumb|Types of second degree AV block]] | ||
*Risk of asystole 35% per year<ref>Burns E. AV Block: 2nd degree, Mobitz II. Life in the Fast Lane. http://lifeinthefastlane.com/ecg-library/basics/mobitz-2/.</ref> | *A disturbance of atrial impulse conduction, usually in the distal conduction system<ref>Jones, W., and Napier, L. Atrioventricular block second-degree. Statpearls. Jan 2019</ref> | ||
*Often associated with structural heart disease | |||
*Significant risk of hemodynamic instability, symptomatic bradycardia, and decompensation into [[Third Degree AV Block]] and subsequent cardiac arrest | |||
**Risk of asystole 35% per year<ref>Burns E. AV Block: 2nd degree, Mobitz II. Life in the Fast Lane. http://lifeinthefastlane.com/ecg-library/basics/mobitz-2/.</ref> | |||
== | ==Clinical Features== | ||
* | *Most patients are asymptomatic | ||
* | *Symptomatic patients may present with: | ||
* | **[[Chest pain]] | ||
[[ | **[[Hypotension]] | ||
**[[Bradycardia]] | |||
**[[Altered mental status]] | |||
**[[Syncope]], [[weakness]] | |||
== | ==Differential Diagnosis== | ||
{{Heart block DDX}} | |||
== | ==Evaluation== | ||
{{Heart block evaluation workup}} | |||
===Diagnosis=== | |||
*[[ | *[[ECG]] findings: | ||
* | **Fixed PR interval for conducted QRS complexes | ||
* | **Intermittent non-conducted P-waves | ||
* | **P waves march through (beware of p-waves consistently buried in T-waves) | ||
* | |||
* | |||
* | |||
==Management== | ==Management== | ||
* | *If symptomatic, standard [[ACLS guidelines for symptomatic bradycardia]] includes<ref name="Sovari">Sovari AA et al. Second-Degree Atrioventricular Block Treatment & Management. eMedicine. Apr 28, 2014. http://emedicine.medscape.com/article/161919-treatment#showall.</ref> | ||
**Atropine 0. | **[[Atropine]] 0.5mg IV q3-5min PRN | ||
**Transcutaneous pacing, followed by transvenous pacing | **[[Transcutaneous pacing]], followed by [[transvenous pacing]] | ||
*Treat underlying etiology | *Treat underlying etiology | ||
*Avoid AV nodal blocking agents ( | *Avoid AV nodal blocking agents (e.g. [[β-blockers]]) | ||
==Disposition== | ==Disposition== | ||
*Admission for pacing and monitoring | *Admission for pacing and monitoring | ||
*Subsequent permanent pacemaker | *Subsequent permanent pacemaker | ||
*2:1<ref | *2:1<ref name="Sovari" /> and 3:1 blocks | ||
**May be unable to determine if [[Second Degree AV Block Type I]] or type II | **May be unable to determine if [[Second Degree AV Block Type I]] or type II | ||
**Admit to cardiology and assume type II | **Admit to cardiology and assume type II | ||
== | ==See Also== | ||
*[[AV blocks]] | |||
==References== | |||
<references/> | <references/> | ||
[[Category:Cardiology]] | [[Category:Cardiology]] |
Latest revision as of 15:21, 21 December 2020
Background
- A disturbance of atrial impulse conduction, usually in the distal conduction system[1]
- Often associated with structural heart disease
- Significant risk of hemodynamic instability, symptomatic bradycardia, and decompensation into Third Degree AV Block and subsequent cardiac arrest
- Risk of asystole 35% per year[2]
Clinical Features
- Most patients are asymptomatic
- Symptomatic patients may present with:
Differential Diagnosis
Differential includes ischemic events, electrolyte abnormalities, and medication overdoses in addition to rheumatologic conditions[3][4]
- Anterior MI
- Rheumatic fever
- Myocarditis
- Lyme disease
- Lenegre's disease
- Lev's disease
- SLE
- Systemic sclerosis
- Amyloidosis
- Hemochromatosis
- Sarcoidosis
- Hyperkalemia
- Toxicology
AV blocks
- First degree AV block
- Second degree
- Third degree AV block
- AV dissociation without complete heart block
Bundle and Fascicular Blocks
- Right Bundle Branch Block
- Left Bundle Branch Block
- Left Anterior Fascicular Block
- Left Posterior Fascicular Block
- Trifascicular Block
Premature Beats
Evaluation
Workup
Diagnosis
- ECG findings:
- Fixed PR interval for conducted QRS complexes
- Intermittent non-conducted P-waves
- P waves march through (beware of p-waves consistently buried in T-waves)
Management
- If symptomatic, standard ACLS guidelines for symptomatic bradycardia includes[5]
- Atropine 0.5mg IV q3-5min PRN
- Transcutaneous pacing, followed by transvenous pacing
- Treat underlying etiology
- Avoid AV nodal blocking agents (e.g. β-blockers)
Disposition
- Admission for pacing and monitoring
- Subsequent permanent pacemaker
- 2:1[5] and 3:1 blocks
- May be unable to determine if Second Degree AV Block Type I or type II
- Admit to cardiology and assume type II
See Also
References
- ↑ Jones, W., and Napier, L. Atrioventricular block second-degree. Statpearls. Jan 2019
- ↑ Burns E. AV Block: 2nd degree, Mobitz II. Life in the Fast Lane. http://lifeinthefastlane.com/ecg-library/basics/mobitz-2/.
- ↑ Hampton, JR. The ECG in Practice (5th edition), Churchill Livingstone 2008.
- ↑ Wagner, GS. Marriott’s Practical Electrocardiography (11th edition), Lippincott Williams & Wilkins 2007.
- ↑ 5.0 5.1 Sovari AA et al. Second-Degree Atrioventricular Block Treatment & Management. eMedicine. Apr 28, 2014. http://emedicine.medscape.com/article/161919-treatment#showall.