Wednesday, August 19, 2015

A very elderly woman with a pacemaker and minimal symptoms

This was a very elderly woman with a pacemaker and minimal symptoms:
What are these broad complexes superimposed on the native QRS?  Are they paced?

These cannot be anything other than artifact.

Although they are regular, and appear in every lead, they occur during the ventricular refractory period during beats 1, 2, 3, and 4, and these ones also are identical to those which are between ventricular beats.

I do not know what was causing this.


  1. These can be muscular movements synced with cardiac beats. I don't know the cause, but I sometimes had such "jerks" about ten years ago.

  2. Replies
    1. It cannot be bigeminy because the supposed PVC happens before the T-wave.

  3. The regularity in artifact-artifact interval and in the amplitude is highly suggestive of an artificial/electrical source of the signal such as a noncardiac pacemaker, rather than from tremor, movement, etc... I believe both the frequency and duration of the artifact overlap with the normal operating range of a spinal cord stimulator (though I would have expected that to have been mentioned the history...)

  4. Her pacemaker isn't sensing and is pacing her phrenic nerve or her pectoralis


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