Understanding the QRS complex in ECGs

Started by ubwcolt
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ubwcolt

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Now, I understand that the QRS represents ventricular depolarization, but I'm still having trouble grasping how it records the electrical impulse.
For now I'm just talking about normal sinus rhythm.
Let's start with the R wave. Does this represent the electrical impulse traveling from the AV node to the Bundle of His, or is the R wave after the impulse has reached the Bundle of His, and the ventricles have already started depolarizing?
Why is the QRS complex pointy? Is it just showing that between both ventricles the electrical current gets stronger and stronger until it peaks, then it abruptly gets weaker and weaker until there is no more electrical current generated by the ventricular tissue?
I'm having a hard time putting together what little I know from the dumbed down version of EKGs we learn in paramedic school, what I understand about how the heart contracts, and what I've learned about the Sodium/Potassium pump and how it effects the electrical charge of cells during depolarization. If anyone can shed some light on this it'd be greatly helpful.
 
You would probably get a faster and more enthusiastic response in the med student forum.