Second degree AV block type I: Difference between revisions
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==Background== | ==Background== | ||
[[File:Second degree heart block.png|thumb|Types of second degree AV block]] | |||
*Also known as a Mobitz I or Wenkebach AV block | *Also known as a Mobitz I or Wenkebach AV block | ||
*Disturbance of atrial impulse conducting through the AV node | *Disturbance of atrial impulse conducting through the AV node | ||
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*Usually asymptomatic | *Usually asymptomatic | ||
*Those who are symptomatic may present with: | *Those who are symptomatic may present with: | ||
** | **[[Dizziness|Lightheadedness/dizziness]] | ||
**Presyncope or [[syncope]] | |||
**Presyncope or syncope | |||
==Differential Diagnosis== | ==Differential Diagnosis== | ||
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==Evaluation== | ==Evaluation== | ||
===Workup=== | |||
*[[ECG]] | *[[ECG]] | ||
===Diagnosis=== | |||
[[File:Type I A-V block 5-to-4 Wenckebach periods.png|thumb|Type I A-V block (5:4) with acute inferior infarction]] | |||
*[[ECG]] with: | |||
**Progressive prolongation of PR interval on consecutive beats | **Progressive prolongation of PR interval on consecutive beats | ||
**Dropped QRS beat not conducted to ventricle after maximal PR prolongation | **Dropped QRS beat not conducted to ventricle after maximal PR prolongation | ||
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==Management== | ==Management== | ||
*Generally benign condition that does not require management after ruling out [[MI]], [[drug overdose|drug toxicity]], [[electrolyte imbalance]] and other unusual causes | |||
*Symptomatic patients can be treated with [[atropine]] or [[isoproterenol]] to transiently improve conduction or with transcutaneous or transvenous pacing if there is associated hypotension<ref> Jones, W., and Napier, L. Atrioventricular block second-degree. Statpearls. Jan 2019</ref> | |||
==Disposition== | ==Disposition== | ||
*Generally outpatient | *Generally outpatient | ||
*2:1 block<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> | *2:1 block<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> | ||
**May be unable to determine if Type I or | **May be unable to determine if Type I or Type II | ||
**If so, assume [[Second Degree AV Block Type II|type II]] and admit with cardiology | **If so, assume [[Second Degree AV Block Type II|type II]] and admit with cardiology consult | ||
==See Also== | ==See Also== |
Latest revision as of 16:05, 26 September 2019
Background
- Also known as a Mobitz I or Wenkebach AV block
- Disturbance of atrial impulse conducting through the AV node
- Considered more benign than Mobitz II as it is not associated with histological changes
Clinical Features
- Usually asymptomatic
- Those who are symptomatic may present with:
- Lightheadedness/dizziness
- Presyncope or syncope
Differential Diagnosis
AV blocks
- First degree AV block
- Second degree
- Third degree AV block
- AV dissociation without complete heart block
Evaluation
Workup
Diagnosis
- ECG with:
- Progressive prolongation of PR interval on consecutive beats
- Dropped QRS beat not conducted to ventricle after maximal PR prolongation
- After dropped QRS complex, PR interval resets and again begins the cycle of progressive prolongation
Management
- Generally benign condition that does not require management after ruling out MI, drug toxicity, electrolyte imbalance and other unusual causes
- Symptomatic patients can be treated with atropine or isoproterenol to transiently improve conduction or with transcutaneous or transvenous pacing if there is associated hypotension[1]
Disposition
- Generally outpatient
- 2:1 block[2]
- May be unable to determine if Type I or Type II
- If so, assume type II and admit with cardiology consult
See Also
External Links
References
- ↑ Jones, W., and Napier, L. Atrioventricular block second-degree. Statpearls. Jan 2019
- ↑ Sovari AA et al. Second-Degree Atrioventricular Block Treatment & Management. eMedicine. Apr 28, 2014. http://emedicine.medscape.com/article/161919-treatment#showall.