What are the management options for a patient who is atrial sensed (AS) and ventricular paced (VP)?

Management Options for Atrial Sensed and Ventricular Paced (AS-VP) Patients

The optimal management for patients with atrial sensed and ventricular paced rhythm is to maintain atrioventricular (AV) synchrony through appropriate pacemaker programming while minimizing unnecessary ventricular pacing when possible. 1

Understanding AS-VP Rhythm

• AS-VP indicates a pacemaker that is sensing normal atrial activity but must pace the ventricle due to impaired AV conduction 2, 1
• This pattern is commonly seen in patients with:
  • AV block (complete or high-grade) with normal sinus node function 1
  • Intact atrial sensing but impaired ventricular conduction 2

Pacing Mode Options

VDD Mode

• Single-lead system with ventricular pacing electrode at the tip and atrial sensing electrodes on the lead body 1
• Detects natural atrial activity and paces the ventricle after a programmed AV interval 1
• Maintains AV synchrony without requiring atrial pacing 2
• If atrial rate falls below programmed minimum, functions as VVI mode 1
• Best suited for patients with:
  • Normal sinus node function 1
  • Complete or high-grade AV block 1
  • Need for hemodynamic benefit from atrial contribution 1

DDD Mode

• Dual-chamber pacing that provides both atrial and ventricular pacing capabilities 2
• Allows for AV synchrony with backup atrial pacing if needed 2
• Recommended for patients with:
  • Intermittent sinus node dysfunction and AV block 2
  • Risk of developing sinus bradycardia 2

Programming Considerations

Minimizing Unnecessary Ventricular Pacing

• Program longer AV delays when possible to allow intrinsic conduction 3
• Use AV search hysteresis algorithms if available to promote intrinsic conduction 4
• Unnecessary RV pacing has been associated with:
  • Increased risk of atrial fibrillation 5
  • Potential for heart failure development 3
  • Ventricular dyssynchrony 3

Rate Response Settings

• Consider rate-responsive features (DDDR/VDDR) for patients with chronotropic incompetence 2
• Adjust upper tracking rate to prevent rapid ventricular pacing during exercise or atrial tachyarrhythmias 2

Ventricular Rate Stabilization

• For patients with atrial fibrillation and AV block, ventricular rate stabilization algorithms can reduce symptomatic rate variability 6
• Setting a pacing rate close to the mean ventricular rate can reduce variability without excessive increase in overall heart rate 6

Special Considerations

Atrial Fibrillation Prevention

• Atrial-based pacing (maintaining AS-VP when possible) is associated with lower risk of AF compared to ventricular-only pacing 2
• Maintaining AV synchrony through appropriate pacing helps prevent retrograde ventriculoatrial conduction, which can cause valvular regurgitation and stretch-induced changes in atrial electrophysiology 2
• However, specific AF prevention algorithms have shown limited efficacy in clinical trials 4

Monitoring Requirements

• Regular device checks to ensure:
  • Appropriate sensing of atrial activity 2
  • Proper AV delay programming 3
  • Battery status and lead impedance 2
  • Percentage of ventricular pacing (aim to minimize if possible) 7

Long-term Considerations

• Monitor for development of pacemaker syndrome 1
• Assess for progression of conduction disease that might require mode changes 7
• Evaluate for ventricular dyssynchrony if high percentage of ventricular pacing is required 3

Pitfalls to Avoid

• Failing to recognize atrial undersensing, which can lead to inappropriate ventricular pacing 2
• Setting AV delays too short, causing unnecessary ventricular pacing 3
• Ignoring the potential long-term consequences of right ventricular pacing on cardiac function 3
• Not considering alternative pacing sites (His bundle, left bundle branch) for patients requiring high percentage of ventricular pacing 3