First of all, I am unclear as to whether the answer to this question is a matter of fact or of opinion. Nevertheless, I hope to find the answer.

In the image below, is the green beat considered ectopic?enter image description here

  • $\begingroup$ What do you think, and why? $\endgroup$ – anongoodnurse Sep 23 '17 at 22:57

For reference: a normal P QRS from an EKG P and QRS from ekg from https://www.healio.com/cardiology/learn-the-heart/ecg-review/ecg-interpretation-tutorial/qrs-complex

The question and the different looking beat: one cannot say it is ectopic because the strip represents some sort of atrial arrhythmia. Atrial fibrillation is the most common of these. The beats are not regularly spaced and there is no sign of a P wave (the one produced by the atrium).

From link

Atrial Fibrillation occurs when multiple electrical impulses occur within within the atria. This chaotic electrical activity results in a chaotic wave form between the QRS complexes. P waves are absent. They are replaced by lower case "f" waves. No P waves means there is no PR interval measurement. This rapid electrical activity overwhelms the AV node causing impulses to enter the ventricular conduction system at irregular points. This results in irregular R to R intervals.

"Ectopic" beat suggests there is a regular beat going on and some rogue beat elbows its way in. In A fib they are all rogue beats - "multiple electrical impulses". The one you see is not in structure different from the rest - there is a T for every QRS and so they are all coming from the atrium. It is just that with that beat the S wave is deeper. Maybe because it is so close to the T? I bet if you ran that strip a while you would see others comparably deep.

I am betting this is homework. What exactly is the question?

  • $\begingroup$ Thanks for your assistance Will. I had the assumption that even in atrial fibrillation, there is some ventricular rhythm to be studied, given by the RR intervals of suitably "normal" beats. Essentially I was wondering whether the size of the beat would qualify it as "not-normal," meaning not part of the intrinsic ventricular rhythm, if any. $\endgroup$ – Open Season Sep 24 '17 at 0:05
  • $\begingroup$ And you are right in predicting that there are more beats with the same S-depth as the green one, though they are fairly sparse. $\endgroup$ – Open Season Sep 24 '17 at 0:07
  • $\begingroup$ this isn't biology, this is medicine. go to the medicine stack exchange $\endgroup$ – 4D Neuron Sep 24 '17 at 1:12
  • $\begingroup$ Beats coming from within the ventricle look different - wide weird QRS. Google up PVC or premature ventricular contraction to see a common type. $\endgroup$ – Willk Sep 24 '17 at 1:14
  • $\begingroup$ @4DNeuron This post is considered as on-topic. Please see here for further details. Also, there are tags that directly support the topic of this question, so I don't see a problem. $\endgroup$ – user22020 Sep 24 '17 at 5:52

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