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Failure (Loss) to Capture - Pacemaker Rhythms.

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  • When a pacemaker loses its ability to cause depolarization (capture), the inherent rhythm of the patient will become present within the tracing.
  • As mentioned earlier in this presentation you will note the presence of a pacing spike, but you will not see a waveform immediately following it.
  • You will likely see a delay after the spike, then the presence of some waveform of different morphology
pacemaker ecg image 109

Practice Strip

pacemaker ecg image 110

Analyze this tracing using the five steps of rhythm analysis.

Show Answer
  • Rhythm: Irregular
  • Rate: 80
  • P Wave: absent
  • PR interval: n/a
  • QRS: 0.14 sec, two non-captured complexes 0.16 sec, all wide and bizarre
  • Interpretation: Ventricular Pacemaker Rhythm with Loss of Capture

Authors and Reviewers

Authored by Thomas O'Brien
Medically reviewed by Dr. Jonathan Keroes, MD, Cardiology
Last Update: 11/8/2020

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