Playlist

Ectopic Foci and Abnormal Conduction – Heart Rate and Electricity

by Thad Wilson, PhD

My Notes
  • Required.
Save Cancel
    Learning Material 2
    • PDF
      Slides HeartRateAndElectricity CardiacPhysiology.pdf
    • PDF
      Download Lecture Overview
    Report mistake
    Transcript

    00:01 Now, what happens if you don't get that conduction past the AV node? Remember, Purkinje fibers can beat on their own.

    00:12 They beat very slow, though, right? 30 to 40 beats per minute.

    00:17 That’s a slow, slow beat.

    00:21 But if you don't get enough information, they will take over and beat anyway.

    00:26 And these generate ectopic foci, a place in the ventricle, that decides, I didn't get enough information, I don't know when I should beat, I'm just going to beat anyway, you can't stop, I’m beating because, you know, why not? That's what happens.

    00:44 They take over their heart rate and they will beat on their own if they don't get enough signal.

    00:50 So, unless you get SA node, AV node signals down the ventricular myocytes and the Purkinje fibers will take over beating.

    01:00 This causes havoc.

    01:03 It makes the QRS complex very wide and creates a process called a premature ventricular complex.

    01:12 And these PVCs are seen very often in electrocardiogram.

    01:17 And the reason why they happen is because the Purkinje fibers did not get signal from the SA node or the AV node.

    01:27 You might ask, at this point, well, why don't they beat on their own anyway? I mean, because, you know, they have that intrinsic rhythm, right, 30 to 40 beats.

    01:38 The reason why they normally don't take over beating is because every time an action potential comes through, it resets the clock.

    01:48 So, if you have something like a sinoatrial node that beats 60 to 100 times per minute, it's going to reset the clock of the AV node and Purkinje fibers every time it happens.

    01:59 So, you'd have to have a block in the system for those other pacemaker cells to take over.


    About the Lecture

    The lecture Ectopic Foci and Abnormal Conduction – Heart Rate and Electricity by Thad Wilson, PhD is from the course Cardiac Physiology.


    Included Quiz Questions

    1. Wide QRS complex
    2. Irregular ventricular response
    3. Variation in P wave contour
    4. Absent QRS complex
    5. P wave after QRS complex

    Author of lecture Ectopic Foci and Abnormal Conduction – Heart Rate and Electricity

     Thad Wilson, PhD

    Thad Wilson, PhD


    Customer reviews

    (1)
    5,0 of 5 stars
    5 Stars
    1
    4 Stars
    0
    3 Stars
    0
    2 Stars
    0
    1  Star
    0
     
    Excellent lecturer
    By Emilio L. on 28. June 2020 for Ectopic Foci and Abnormal Conduction – Heart Rate and Electricity

    I like professor Thad's lectures. He explains a little bit slow but is great because for non-english native speakers is good for understand the main concept of the lecture