Syncope during complete atrioventricular block

This clinical and electrocardiographic presentation likely corresponds to idiopathic paroxysmal atrioventricular block with

1. several episodes of unexplained syncope without clear trigger,
2. an initial ECG that shows no conduction abnormality,
3. absence of structural heart disease,
4. observation, in the wake of syncope, of sudden complete atrioventricular block, without a marked increase in the PR interval or change in heart rate preceding the episode. In this patient, the increase in PR interval before the pause is minimal, and the heart rate remains stable, while the atrial rate accelerates moderately at the time of the pause.

The ILR revealed a conduction disorder previously difficult to demonstrate. This patient underwent implantation of a pacemaker, which prevented further recurrences. Permanent pacing has been uniformly effective in similar cases published in the medical literature. This clinical case highlights the advantages and limitations of this type of device. On the one hand, a diagnosis was made after recurrence of syncope complicated by facial trauma. On the other, it seemed unacceptable to proceed with a pacemaker implant as a first step in this patient, whose ECG was normal and electrophysiological studies were non-contributory.

The activation of the ILR after the onset of an episode, using the Patient Assistant, may be impossible by patients who have

1. suffered a trauma and are temporarily motionless or stunned by a fall,
2. a permanent cognitive disorder, or
3. limited mobility or manual dexterity. In such cases, an automatic recording may allow the rendering of a diagnosis, as illustrated here.