Management of atrial arrhythmias

Device: PM Field: Management of atrial arrhythmias

1. Basic concepts



The management of cardiac pacemaker recipients who present with episodes of atrial arrhythmias is complex because of the risk of run away of ventricular pacing by tracking of a rapid atrial rhythm. From a continuous analysis of the atrial rhythm, mode switch causes the automatic transition from an atrial tracking DDD or VDD, to a non-atrial tracking DDI pacing mode. The fallback algorithm prevents ventricular pacing at high rates, synchronized to the rates of atrial arrhythmias. An ideal mode switch algorithm combines the following characteristics:

  • rapid onset to avoid rapid ventricular pacing during the initial phase of sensing of the arrhythmia
  • ability to return rapidly to a synchronous mode at the end of the arrhythmic episode
  • high diagnostic accuracy of atrial arrhythmias despite the presence of atrial electrograms of variable rate and amplitude
  • capable of avoiding mode switch in response to far-field sensing, noise or sinus tachycardia

The pacemaker automatically records the diagnostic data of the various arrhythmic episodes to assist in the management of these patients and, perhaps, modify their treatment.

Some additional algorithms serve to prevent arrhythmias and can be programmed to prevent pacing in the vulnerable period, or to pace rapidly to counteract the mechanisms promoting the onset of atrial tachyarrhythmias:

  • non-competitive atrial pacing prevents the trigger of an atrial arrhythmia, which might be caused by pacing in the atrial relative refractory period following an atrial extrasystole, by observing a minimum escape interval after the extrasystole;
  • stabilization of the atrial rhythm adapts the pacing rate in response to an atrial extrasystole to eliminate long sinus pauses following short cycles;
  • atrial preference pacing forces a continuous atrial pacing slightly faster than the spontaneous rhythm;
  • post-mode switch overdrive pacing can be added to the mode switch function to pace the atrium rapidly when DDD mode returns after the end of an atrial arrhythmic episode;
  • the “conducted AF response” regularizes the ventricular rate during episodes of atrial fibrillation, thus preventing prolonged pauses.



Mode switch is an ON / OFF programmable function designed to prevent the tracking of paroxysmal atrial tachycardias when the pacemaker operates in DDD, VDD or MVP modes.

We send back to you to the specificities of every manufacturer to know the various algorithms of switching of mode and other specific programs of management of atriales arrhythmias.

2. Specificities by company