Recent studies have shown the importance of preserving spontaneous atrio-ventricular conduction in patients implanted with an implantable cardiac pacemaker.

The SafeR/AAISafeR pacing mode, developed by Sorin Group/ELA Medical and available on Reply and SymphonyTM dual-chamber pacemakers, provides physiological atrial pacing while ensuring ventricular backup pacing in case of AV block in patients implanted for Sinus Dysfunction, Brady Tachy Syndrome or paroxysmal Atrio Ventricular block3 (AV block).

Memory functions (EGM episodes and Marker chains) available with the SafeR/AAISafeR pacing mode have been used until now to verify the safety of the algorithm. However, these stored EGM episodes and Marker chains may also provide precious information related to the nature of the AV block and the evolution of conduction disorders through time.

So far no studies have been carried out on this subject using the latest generation of pacemakers. This results from the unavailability of any diagnostic tool in currently marketed devices. Studies reporting the incidence of AV block in patients implanted for Sinus Dysfunction are based only on the occurrence of symptomatic AV block and/or the observation of conduction disorders on surface ECG during follow-up4,5.

The diagnostic functions available with the SafeR/AAISafeR mode enable to diagnose and record in device memory all AV blocks, regardless of the degree of the AV block and the symptom(s) of the patient. Therefore, this unique diagnostic tool could enable to determine the nature and to analyze through time the evolution of conduction disorders in patients implanted for Sinus Dysfunction, Brady Tachy Syndrome or paroxysmal Atrio Ventricular block, in order to better identify the indications for implant and to provide further appropriate pacing mode.

The observational study will enable to compile all these device memory data in order to directly assess statistical analysis of AV block incidence and evolution according to the nature of the AV block, the incidence of paroxysmal atrial arrhythmias, the anti arrhythmic drugs medication and other.