Examine the trace from a patient with a pacemaker  in the DDD mode.   What problem is seen with this pacemaker?

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College Answer

Failure to sense the atrium

Discussion

The pacing spike seen after a normal P wave suggests the pacemaker has failed to detect normal atrial activity. The rhythm strip I used up there comes from a Medscape article.

References

References

Wiegand, Uwe KH, et al. "Diagnosis of atrial undersensing in dual chamber pacemakers: impact of autodiagnostic features.Pacing and clinical electrophysiology 22.6 (1999): 894-902.