Can a patient with a pacemaker (pacer) be in atrial fibrillation (afib) with a heart rate in the normal range, specifically in the 60s?

Atrial Fibrillation with Pacemaker and Heart Rate in the 60s

Yes, a patient can have atrial fibrillation while having a heart rate in the 60s with a pacemaker. This occurs when the pacemaker regulates the ventricular response despite ongoing atrial fibrillation.

Mechanism of Pacemaker-Controlled AF

• Pacemakers can regulate ventricular rhythm during AF by eliminating longer ventricular cycles and reducing short cycles related to rapid AV conduction 1
• When a patient has a pacemaker (particularly after AV nodal ablation), the device controls the ventricular rate regardless of the chaotic atrial activity occurring during AF 1
• Pacing at approximately the mean ventricular rate during spontaneous AV conduction can effectively regulate ventricular rhythm during AF 1

Clinical Scenarios Where This Occurs

• AV Nodal Ablation with Pacemaker: Most common scenario where a patient has controlled AF with a regular heart rate in the 60s 1

  • After AV nodal ablation, the pacemaker becomes the primary controller of ventricular rate 1
  • This provides highly effective control of heart rate and improves symptoms in selected patients 1

• VVI Pacing in AF: VVI pacemakers are commonly set with a lower limit of 60 bpm in patients with bradycardic AF 2

  • Research shows that cardiac output increases at pacing rates of 60-70 bpm in bradycardic AF patients 2

• Dual-Chamber Pacing: In patients with dual-chamber pacemakers, the device can detect atrial high-rate episodes (AHRE) while maintaining a controlled ventricular rate 3

  • These episodes may represent asymptomatic AF while the ventricular rate remains controlled 3

Diagnostic Considerations

• When AF occurs in a patient with a pacemaker, diagnosis may require temporary pacemaker inhibition to expose fibrillatory activity 1
• In pacemaker patients, AF may be detected as "atrial high-rate events" which can occur without symptoms 1
• ECG findings may show irregular atrial activity with regular ventricular pacing spikes and QRS complexes 1

Clinical Implications

• Patients with AF and pacemakers still require anticoagulation based on stroke risk factors, despite controlled heart rates 1
• Bradycardia-related AF can sometimes be eliminated when the bradycardia is addressed through appropriate pacing 4
• Some patients may develop bradycardia-tachycardia syndrome (sick sinus syndrome) where both AF and bradycardia coexist 4

Management Considerations

• For patients with symptomatic AF and inadequate rate control despite medications, AV nodal ablation with permanent pacemaker implantation is an effective strategy 1
• The optimal pacing rate may vary, but research suggests cardiac output increases at pacing rates of 70/min compared to 60/min in bradycardic AF patients 2
• Current guidelines recommend a lenient heart rate control target of <110 bpm at rest as the initial goal for most AF patients 1, 5

In conclusion, the presence of a pacemaker allows for controlled ventricular rates in patients with AF, making it entirely possible for patients to have ongoing atrial fibrillation with heart rates maintained in the 60s through pacemaker function.