Retrograde Wenckebach and Reentry

Report:

Pacemaker rhythm 92/min 1

Retrograde Wenckebach conduction 4

Wenckebach sequences terminated by reentry (echo) beats of pacemaker origin 4

Non-specific T wave changes 1

Comment:

The pacemaker is in its rate-responding mode at 92/min, with Wenckebach conduction to the atria interrupted by reentry beats. The latter do not have retrograde conduction – these are the only two cycles without any P waves behind the QRS complex. The following cycles have an RP interval of 0.28”, increasing to 0.48” before the next reentry. The longer the VA interval, the greater the likelihood of reentry. The patient thus demonstrates both retrograde and antegrade conduction through her AV node.

The T wave changes (of the two normally conducted QRS complexes) may reflect cardiac memory54 of pacemaker repolarisation or of course any of the other causes of T wave inversion.

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