Trigeminy with a Pacemaker

Report:

Sinus rhythm 90/min

AV block, undefined

AV dissociation

Pacemaker rhythm 48/min

Failure to sense

Ventricular fusion beat

VEBs, interpolated

Sinus capture beats, with first degree AV block

Comment:

The VEBs are interpolated between the LBBB-like paced beats, or between sinus captures and the paced beats. This is one variety of interpolation where no difference in cycle length is apparent between the cycles containing the VEB and the “empty” pacemaker cycles.

The sinus capture beats are only slightly early with respect to the paced rhythm. Theirs’ are the only normal QRSs in the strips. It is uncertain what the conduction would be without the paced and the ventricular ectopic beats; it is one of those “block/acceleration dissociation” situations aptly described by Marriott121. The 10th complex in the bottom strip, more slender than its counterparts, is probably a fusion beat: it is preceded by an appropriately placed P wave.

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