Is nebivolol safe to prescribe for a patient with second‑degree type II (Mobitz II) or third‑degree atrioventricular block who does not have a permanent pacemaker?

Nebivolol is Absolutely Contraindicated in Patients with Mobitz II or Third-Degree AV Block Without a Permanent Pacemaker

Do not prescribe nebivolol to any patient with second-degree type II (Mobitz II) or third-degree atrioventricular block who lacks a permanent pacemaker—this is an explicit FDA contraindication that carries significant risk of life-threatening bradycardia, complete heart block, and sudden cardiac death. 1

FDA-Mandated Contraindications

The FDA drug label for nebivolol explicitly lists the following as absolute contraindications: 1

• Heart block greater than first degree (which includes both Mobitz II and third-degree AV block)
• Severe bradycardia
• Sick sinus syndrome (unless a permanent pacemaker is in place)
• Cardiogenic shock
• Decompensated cardiac failure

The only exception to this contraindication is if the patient already has a functioning permanent pacemaker in place. 1

Guideline-Based Management Framework

For Mobitz II Second-Degree AV Block:

Permanent pacing is mandated regardless of symptoms before any beta-blocker therapy can be considered. The ACC/AHA/HRS guidelines provide a Class I recommendation (highest level) that patients with acquired second-degree Mobitz type II AV block require permanent pacing regardless of symptom status. 2 This is because Mobitz II block:

• Occurs at the infranodal (His-Purkinje) level 3, 4
• Carries high risk of progression to complete heart block 3, 4
• Is associated with unpredictable sudden cardiac arrest 3

For Third-Degree (Complete) AV Block:

Permanent pacing is absolutely required before considering any AV-nodal blocking agent. The ACC/AHA/HRS guidelines give a Class I recommendation that acquired third-degree AV block at any anatomic level not attributable to reversible causes requires permanent pacing regardless of symptoms. 2, 5

Critical Clinical Pitfalls to Avoid

The "Drug-Induced" AV Block Misconception:

Do not assume that discontinuing nebivolol will reliably reverse AV block if it develops. While beta-blockers are traditionally considered "reversible" causes of AV block, recent evidence demonstrates: 6

• True drug-induced AV block is rare in clinical practice
• Most cases represent drug-unmasking of underlying conduction system disease
• Recurrence rates after drug discontinuation are high (27% in one study) 7
• Approximately 50% of patients with "drug-induced" AV block ultimately require permanent pacemaker implantation 7

Specific Beta-Blocker Considerations:

Research shows variable outcomes with different beta-blockers: 7

• Metoprolol-induced AV block: 24 of 36 cases (67%) either persisted or recurred despite drug discontinuation
• Carvedilol-induced AV block: 21 of 24 cases (88%) resolved and did not recur
• Nebivolol-specific data showed 10% of patients developed AV block requiring drug discontinuation 8

However, these data are irrelevant to your clinical scenario because the patient already has established high-grade AV block before drug initiation—this is fundamentally different from drug-induced block.

The Correct Clinical Algorithm

Step 1: Identify the Type of AV Block

• Mobitz II or third-degree block = absolute contraindication to nebivolol 1
• First-degree or Mobitz I block = relative contraindication requiring careful monitoring

Step 2: Assess for Permanent Pacemaker

• If no pacemaker present: Do not prescribe nebivolol under any circumstances 1
• If permanent pacemaker present: Nebivolol may be prescribed with appropriate monitoring

Step 3: If Pacemaker Not Present, Refer for Permanent Pacing

The ACC/AHA/HRS guidelines mandate permanent pacemaker implantation for: 2, 9, 5

• All Mobitz II second-degree AV block (Class I, Level B-NR)
• All third-degree AV block not due to reversible causes (Class I, Level B-NR)
• This recommendation applies regardless of symptoms

Step 4: Only After Pacemaker Placement

• Nebivolol can be considered if clinically indicated
• The pacemaker provides backup ventricular pacing if complete heart block develops
• Continue monitoring for appropriate pacemaker function

Special Consideration: "Guideline-Directed Therapy" Exception

The ACC/AHA/HRS guidelines do recognize one scenario where permanent pacing is recommended to enable continuation of necessary medications: 2, 9

"In patients who develop symptomatic atrioventricular block as a consequence of guideline-directed management and therapy for which there is no alternative treatment and continued treatment is clinically necessary, permanent pacing is recommended." (Class I, Level C-LD) 2

However, this applies to patients who develop AV block while on therapy, not to patients with pre-existing high-grade AV block in whom you are considering initiating beta-blocker therapy. The distinction is critical: you cannot use this exception to justify starting nebivolol in a patient who already has Mobitz II or third-degree block without a pacemaker.

Bottom Line

Nebivolol is absolutely contraindicated by the FDA in patients with heart block greater than first degree who do not have a permanent pacemaker. 1 The ACC/AHA/HRS guidelines mandate permanent pacemaker implantation for all patients with Mobitz II or third-degree AV block regardless of symptoms before any AV-nodal blocking medications can be safely prescribed. 2, 9, 5 There is no clinical scenario in which initiating nebivolol in a patient with established Mobitz II or third-degree AV block without a pacemaker is appropriate—doing so exposes the patient to unacceptable risk of complete heart block, syncope, and sudden cardiac death.