What is the management for a patient with an atrioventricular block (AVB) who has a permanent pacemaker (PPM) in place?

Management of Patients with Permanent Pacemaker and Atrioventricular Block

For a patient with an existing permanent pacemaker (PPM) and atrioventricular block (AVB), the primary management focus is ensuring proper pacemaker function through interrogation and programming optimization, monitoring for complications, and addressing any underlying reversible causes of worsening conduction disease. 1

Immediate Assessment and Device Interrogation

The pacemaker must be interrogated to verify appropriate sensing, pacing thresholds, and programming. 1 Key parameters to evaluate include:

• Pacing mode appropriateness: Confirm the device is programmed to provide adequate ventricular pacing support for the degree of AVB present 1
• Lead integrity: Assess sensing and capture thresholds to ensure reliable pacing 1
• Battery status: Verify adequate generator longevity 1
• Pacing percentage: Document ventricular pacing burden, as high-degree AVB typically requires near-continuous ventricular pacing 2

Pacing Mode Optimization

In patients with AVB and intact sinus node function, dual-chamber pacing (DDD) is recommended over single-chamber ventricular pacing (VVI) to maintain atrioventricular synchrony and reduce risk of pacemaker syndrome. 1

• For complete AVB with normal sinus rhythm, DDD mode provides physiologic atrioventricular coordination 1
• Single-lead VDD pacing can be considered as an alternative in AVB patients without sinus node dysfunction, with comparable long-term outcomes to DDD 2
• Avoid VVI pacing in symptomatic AVB patients due to loss of atrioventricular synchrony, which causes pacemaker syndrome (fatigue, dyspnea, hypotension) 1

Evaluation for Reversible Causes

Even with a PPM in place, assess for new or worsening reversible causes of AVB that may require specific treatment beyond pacing: 1

• Medication review: Beta-blockers, calcium channel blockers, digoxin, antiarrhythmics may worsen conduction 1
• Lyme carditis: Consider in endemic areas; may respond to antibiotics 1
• Electrolyte abnormalities: Hyperkalemia can worsen AVB 1
• Acute myocardial infarction: New ischemia can cause transient worsening of conduction 1
• Cardiac sarcoidosis: May require immunosuppression and consideration for defibrillator upgrade 1

Perioperative Management

For patients with PPM undergoing non-cardiac surgery, specific precautions are mandatory: 1

• Preoperative device interrogation is required to document baseline function 1
• Reprogram to asynchronous mode (DOO/VOO) if patient is pacemaker-dependent and electrocautery will be used 1
• Use bipolar electrocautery when possible; position grounding pad away from the device 1
• Postoperative interrogation is necessary to restore appropriate settings and verify proper function 1
• Have external pacing capability immediately available during the procedure 1

Monitoring for Late Complications

Patients with PPM and AVB require ongoing surveillance for device-related complications and progression of conduction disease: 3, 4

• Lead complications: Monitor for lead fracture, dislodgement, or rising thresholds requiring revision 1
• Infection risk: Increased in patients who had temporary pacing wires before permanent implant 5
• Progressive conduction disease: AVB can worsen over time, requiring programming adjustments 3, 4
• Atrial arrhythmias: Development of atrial fibrillation may require anticoagulation and mode switch programming 1

Special Considerations for High-Risk Scenarios

In patients with AVB post-cardiac surgery (aortic or mitral valve), persistent high-grade block beyond 5-7 days warrants PPM if not already present: 1

• Transient AVB after valve surgery is common but usually resolves within days 1
• Persistent symptomatic bradycardia or hemodynamic instability requires permanent pacing before discharge 1

For AVB in the setting of acute MI, a waiting period is recommended before permanent pacing to allow for recovery of conduction, but this does not apply to patients with existing PPMs who should have their devices optimized. 1

Device Upgrade Considerations

Consider upgrading to a cardiac resynchronization therapy device (CRT) or implantable cardioverter-defibrillator (ICD) if: 1

• Left ventricular ejection fraction is reduced and patient requires frequent ventricular pacing 1
• Patient has additional indications for defibrillator therapy (e.g., cardiac sarcoidosis, hypertrophic cardiomyopathy with risk factors) 1
• Meaningful survival >1 year is expected 1

Common Pitfalls to Avoid

• Do not assume the pacemaker is functioning properly without interrogation—device malfunction can occur 6
• Do not use atropine in patients with infranodal AVB—it may paradoxically worsen block 1
• Do not remove or deactivate the device without ensuring adequate intrinsic rhythm—complete AVB patients are pacemaker-dependent 7
• Do not forget to restore normal programming after perioperative reprogramming—leaving asynchronous mode active increases unnecessary pacing 1