What type of pacemaker is recommended for patients with atrioventricular (AV) block or sick sinus syndrome?

Pacemaker Selection for AV Block and Sick Sinus Syndrome

Dual-chamber pacing (DDD/DDDR) is the recommended pacemaker mode for both AV block and sick sinus syndrome, as it maintains atrioventricular synchrony, reduces complications, and prevents pacemaker syndrome. 1

For Sick Sinus Syndrome (SND)

Primary Recommendation

• Dual-chamber pacing (DDD) is strongly recommended over single-chamber ventricular pacing (VVI) in patients with sick sinus syndrome and intact AV conduction (Class I, Level of Evidence: A). 1
• Dual-chamber pacing is also recommended over single-chamber atrial pacing (AAI) in patients with sick sinus syndrome (Class I, Level of Evidence: B). 1

Clinical Rationale

• Patients with sick sinus syndrome have a 3-35% risk of developing AV block within 5 years of pacemaker implantation, making dual-chamber devices essential to avoid reoperation. 2
• The incidence of atrial fibrillation at initial diagnosis ranges from 40-70%, with new AF developing in 3.9-22.3% during follow-up. 1, 2
• Dual-chamber pacing significantly reduces the need for reoperation compared to single-chamber atrial pacing (odds ratio 0.48,95% CI 0.36-0.63). 3
• Dual-chamber pacing reduces paroxysmal atrial fibrillation risk (OR 0.75,95% CI 0.59-0.96) compared to single-chamber atrial pacing. 3

Programming Considerations

• Program dual-chamber pacemakers to minimize unnecessary ventricular pacing to prevent atrial fibrillation (Class IIa, Level of Evidence: B). 1, 2
• Rate-adaptive pacing (DDDR) is useful in patients with significant symptomatic chronotropic incompetence and should be reevaluated during follow-up (Class IIa, Level of Evidence: C). 1

Limited Exceptions

• Single-chamber VVI pacing may be considered only when frequent pacing is not expected or the patient has significant comorbidities likely to influence survival (Class IIb, Level of Evidence: C). 1
• Single-chamber AAI pacing may be considered in highly selected patients with normal AV and ventricular conduction (Class IIb, Level of Evidence: B), but carries a two-fold increased risk of reoperation. 1, 4

For AV Block

Primary Recommendation

• Dual-chamber pacing is recommended in all patients with AV block (Class I, Level of Evidence: C). 1

Acceptable Alternatives

• Single-chamber ventricular pacing (VVI/VVIR) is an acceptable alternative only in specific clinical situations (Class I, Level of Evidence: B): 1

  • Sedentary patients with limited activity levels
  • Patients with significant medical comorbidities likely to impact clinical outcomes
  • Technical issues such as vascular access limitations that preclude or increase the risk of placing an atrial lead
  • Patients in permanent atrial fibrillation where sinus rhythm restoration is not planned

• Single-lead VDD pacing can be useful in patients with normal sinus node function and AV block, particularly younger patients with congenital AV block (Class IIa, Level of Evidence: C). 1, 5

Clinical Benefits

• Dual-chamber pacing maintains atrioventricular synchrony, which prevents pacemaker syndrome (Peto OR 0.11,95% CI 0.08-0.14). 6
• Pooled data shows trends toward reduced stroke, heart failure, and mortality with dual-chamber pacing, though not always statistically significant. 6
• Exercise capacity is significantly improved with dual-chamber pacing (SMD -0.24,95% CI -0.03 to -0.45). 6
• Ten-year survival is superior with dual-chamber pacing: 61% vs 51% for VVI pacing in AV block patients. 7

Critical Contraindications

• Do not use dual-chamber or single-chamber atrial pacing in patients with permanent or longstanding persistent atrial fibrillation where efforts to restore or maintain sinus rhythm are not planned (Class III, Level of Evidence: C). 1, 2
• In these patients, single-chamber ventricular pacing (VVI) is appropriate. 1

Cost-Effectiveness Considerations

• Dual-chamber pacing becomes cost-effective by the third year after implantation for both sick sinus syndrome and AV block, with cumulative costs lower than VVI pacing thereafter. 7
• The base-case incremental cost-effectiveness ratio for dual-chamber vs single-chamber atrial pacing in sick sinus syndrome is £6,506, well below the £20,000 threshold. 3

Common Pitfalls to Avoid

• Do not implant single-chamber atrial pacemakers in sick sinus syndrome patients without considering the high risk of developing AV block requiring reoperation. 2, 4
• Do not delay dual-chamber pacing in AV block waiting for symptoms, as progression can be sudden and unpredictable. 5
• Avoid excessive ventricular pacing in dual-chamber systems by utilizing algorithms that minimize unnecessary ventricular stimulation. 2