"Normal Sinus Rhythm"
on an EKG by KhanAcademyMedicine
- Your typical EKG P-QRS-T complex figure is a Lead II EKG. It records electrical activity from the SA node towards the bottom left part of your heart (your left leg, actually).
- Tiny boxes=0.04sec
- AV node cells are narrow=slow conduction.
- Sodium channels are FAST at depolarizing.
- ST segment=no net current =/= not active--it's when the ventricles are fully contracted--remember, the EKG is the electrical map and it actually precedes the actual contraction.
- The PR wave is measured instead of the PQ wave because sometimes the Q doesn't show up.
- The direction of which the waves and peaks go dictate whether it is the endocardium or epicardium depolarizes and repolorizes first. (Cool--but not really necessary to understand.)
