From the Guidelines
For patients with second-degree AV block, particularly those with Mobitz type II, high-grade AV block, or third-degree AV block not due to reversible causes, permanent pacing is recommended regardless of symptoms. This recommendation is based on the 2019 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1. The guideline suggests that permanent pacing is indicated for these conditions due to the high risk of progression to complete heart block and the potential for significant morbidity and mortality.
When managing second-degree AV block, it's crucial to distinguish between Mobitz type I (Wenckebach) and Mobitz type II, as the approach differs:
- For asymptomatic Mobitz type I, observation may be sufficient, but for symptomatic patients or those with Mobitz type II, more aggressive intervention is necessary.
- Temporary treatments, such as atropine or isoproterenol infusion, may be used in urgent situations, but definitive management often involves permanent pacing.
- Underlying causes, such as AV nodal blocking medications, electrolyte abnormalities, myocardial ischemia, or inflammatory conditions, should be addressed.
Key considerations for permanent pacing include:
- The presence of symptoms attributable to the AV block
- The type of AV block (Mobitz type I vs. type II)
- The presence of underlying conditions, such as neuromuscular diseases or infiltrative cardiomyopathies
- The potential for progression to complete heart block
According to the guideline, permanent pacing is recommended for patients with:
- Acquired second-degree Mobitz type II AV block, high-grade AV block, or third-degree AV block not attributable to reversible or physiologic causes 1
- Neuromuscular diseases associated with conduction disorders, such as muscular dystrophy or Kearns-Sayre syndrome, with evidence of second-degree AV block, third-degree AV block, or an HV interval of 70 ms or greater 1
From the FDA Drug Label
Atropine also may lessen the degree of partial heart block when vagal activity is an etiologic factor The answer to Av block second degree is that atropine may be used to lessen the degree of partial heart block when vagal activity is an etiologic factor 2.
- Key points:
- Atropine may be used to treat Av block second degree
- It works by lessening the degree of partial heart block when vagal activity is an etiologic factor
- Atropine should be used with caution and under medical supervision.