Second degree AV block type II

Background

Types of second degree AV block
  • 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

Differential Diagnosis[3][4]

AV Blocks

Evaluation

2nd degree AV Block Type 2 (4:3 conduction)
2nd degree AVB, 2:1 conduction, LBBB with buried p-waves in t-waves

Workup

  • Evaluate for underlying pathology
  • ECG
  • Labs

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

Disposition

  • Admission for pacing and monitoring
  • Subsequent permanent pacemaker
  • 2:1[5] and 3:1 blocks

See Also

References

  1. Jones, W., and Napier, L. Atrioventricular block second-degree. Statpearls. Jan 2019
  2. Burns E. AV Block: 2nd degree, Mobitz II. Life in the Fast Lane. http://lifeinthefastlane.com/ecg-library/basics/mobitz-2/.
  3. Hampton, JR. The ECG in Practice (5th edition), Churchill Livingstone 2008.
  4. Wagner, GS. Marriott’s Practical Electrocardiography (11th edition), Lippincott Williams & Wilkins 2007.
  5. 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.

Authors:

Ross Donaldson