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R. van der Nagel 0
V. F. van Dijk 0
0 St. Antonius Ziekenhuis , Nieuwegein , The Netherlands
An intracardial electrogram (iEGM) reveals the origin of
this peculiar atrial patterning. First note the regular rhythm
of the ventricle (750 ms, 80 beats per minute (bpm)) (Fig. 1).
Since the patient has a known history of paroxysmal atrial
fibrillation, and had an episode when we changed the
parameters just before surgery, we opted to programme the
device to the asynchronous mode VOO 80 during surgery.
You can recognise the associated far-field R wave (FFRW)
of the paced ventricular activation on the atrial iEGM
channel as well. It is annotated as ‘ab’, as it is registered within
the post-ventricular atrial blanking period. Because of the
VOO mode, there is no absolute blanking and the sinus
rhythm (680 ms, 88 bpm) is not affected by this anomaly.
Dissociation between these two signals causes the pattern
In normal settings (DDD 60-130), this phenomenon does
not occur, as the FFRW is blanked by the device (Fig. 2).
Note that both the intrinsic atrial rhythm (AS) and FFRW
(Ab) are consonant with both signals found in the
electrogram of the episode of atrial tachycardia/atrial fibrillation.
Conflict of interest R. van der Nagel and V.F. van Dijk declare that
they have no competing interests.
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