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Repetitive Nonreentrant Ventriculoatrial synchrony

Repetitive nonreentrant ventriculoatrial synchrony (RNRVAS)

Repetitive Non-Reentry Ventriculo-Atrial Synchronization (RNRVAS)

• VAC (VA Conduction)
• This is the time of retrograde conduction through the AV node (350ms)
• KES (Ventricular Extrasystole)
• Depolarizes the ventricles (QRS) and the impulse travels retrograde through the AV node to the atria
• A retrograde P wave is generated but during the PVARP interval (400ms)
• During the PVARP interval, the pacemaker ignores the retrograde P wave
• AEI (Atrial Escape Interval)
• This is the interval between ventricular pacing and atrial pacing (525ms)
• If within 525ms after ventricular pacing (sensing) no spontaneous P wave occurs
• then the pacemaker activates atrial pacing (Ap)
• However, Ap occurs during the refractory period of the atrial myocardium (MyoRP)
• Thus, the pacemaker-generated P wave (Ap) is blocked
• However, the pacemaker counts the AV interval (225ms) from the blocked P wave (Ap)
• It then initiates ventricular pacing
• The cycle then repeats
  
  
• Repetitive non-reentry VA synchronization is most commonly triggered by
• Ventricular Extrasystole (KES)

Repetitive Non-Reentry VA Synchronization (Termination)

• The patient has a DDD pacemaker
• The fourth beat is a ventricular extrasystole (KES)
• With retrograde conduction
• The fifth beat is a ventricular extrasystole
• With retrograde VA block
• This is followed by effective atrial pacing (Ap) because Ap occurs:
• Outside the PVARP
• Outside the refractory period of the atrial myocardium