Transvenous cardiac pacemakers have pitfalls due to lead- and device pocket-related complications. Leadless pacemakers were developed and introduced into clinical practice to overcome the weaknesses of traditional transvenous pacemakers. The absence of atrial pacing has restricted their uses mainly for cases of paroxysmal atrioventricular block (AVB) or AVB with atrial fibrillation. The Micra AV contains an embedded accelerometer that senses the atrial contraction waveform, allowing the ventricle to be paced once the atrial contraction is complete. This atrioventricular synchronization is intended to extend the use of the device to cases of permanent complete AVB with normal sinus function. Two randomized clinicals trials have been proven it's efficacy. However, with AV-CESAR cohort, we aim to evaluate the real word effectiveness of Micra AV, in the first 1000 patients implanted by the device in France.