Second degree AV block type I
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:
- Light-headedness
- 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
- ECG
- 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
Disposition
- Generally outpatient
- 2:1 block[1]
- May be unable to determine if Type I or type II
- If so, assume type II and admit with cardiology
See Also
External Links
References
- ↑ Sovari AA et al. Second-Degree Atrioventricular Block Treatment & Management. eMedicine. Apr 28, 2014. http://emedicine.medscape.com/article/161919-treatment#showall.