From the Guidelines
For symptomatic patients with Mobitz type I (Wenckebach) second-degree atrioventricular (AV) block, permanent pacing is a reasonable treatment option, as stated in the 2018 ACC/AHA/HRS guideline 1.
Treatment Approach
The treatment of Mobitz type I second-degree AV block depends on the presence of symptoms and the underlying cause.
- Asymptomatic patients without hemodynamic compromise may be observed, as Wenckebach is often benign and transient.
- Symptomatic patients experiencing dizziness, syncope, or fatigue may be administered atropine 0.5-1 mg IV as a temporary measure to increase heart rate, as suggested by the guidelines for the early management of patients with acute myocardial infarction 1.
Permanent Pacing
Permanent pacing is recommended for patients with marked first-degree or second-degree Mobitz type I (Wenckebach) atrioventricular block with symptoms that are clearly attributable to the atrioventricular block, as stated in the 2018 ACC/AHA/HRS guideline 1.
- The guideline recommends permanent pacing for these patients, with a Class IIa recommendation and a Level of Evidence of C-LD.
- Underlying causes such as medication side effects, myocardial ischemia, or electrolyte abnormalities should be addressed by discontinuing offending medications, treating coronary artery disease, or correcting electrolyte imbalances.
Conclusion Not Applicable - Direct Answer Only
The 2018 ACC/AHA/HRS guideline 1 provides the most recent and highest quality evidence for the treatment of Mobitz type I second-degree AV block, and its recommendations should be followed in clinical practice.
From the FDA Drug Label
Atropine also may lessen the degree of partial heart block when vagal activity is an etiologic factor The treatment for Mobitz type I (Wenckebach) second-degree atrioventricular (AV) block is to administer atropine if vagal activity is the cause, as it may lessen the degree of partial heart block 2.
From the Research
Treatment of Mobitz Type I Second-Degree AV Block
- The treatment of Mobitz type I second-degree atrioventricular (AV) block depends on the underlying cause and symptoms of the patient 3.
- In cases where the block is caused by inappropriate sinus tachycardia (IST), treatment with ivabradine may be effective in reducing the occurrence of Wenckebach phenomenon 3.
- Ivabradine works by selectively reducing the impulse conduction within the sinoatrial (SA) node, thereby reducing the beat conduction to the AV node 3.
- In other cases, the treatment may involve addressing the underlying cause of the block, such as stopping medications that may be contributing to the block 3.
- It is also important to distinguish Mobitz type I second-degree AV block from other causes of pauses, such as nonconducted premature atrial contractions and atrial tachycardia with block 4.
Diagnostic Considerations
- The diagnosis of Mobitz type I second-degree AV block is based on the presence of visible, differing, and generally decremental AV conduction on the electrocardiogram (ECG) 5.
- The ECG should show a pattern of progressive prolongation of the PR interval before a blocked P wave, followed by a reset of the PR interval after the blocked P wave 5.
- It is also important to consider the clinical context and other diagnostic criteria, such as the presence of symptoms and the results of other diagnostic tests, such as echocardiography and Holter monitoring 3, 6.
Prognosis and Management
- The prognosis and management of Mobitz type I second-degree AV block depend on the underlying cause and symptoms of the patient 4, 5.
- In general, Mobitz type I second-degree AV block is considered to be a relatively benign condition, but it can be a sign of underlying cardiac disease and may require further evaluation and treatment 4, 5.
- In some cases, pacing may be required to manage symptoms and prevent complications, such as syncope and heart failure 5.