We are studying the cardiac system in phys and I am needing any and all websites that deal with cardiac conduction.... especially learning the ECG.
Any websites that have to do with reading EKG's would be so helpful. Our text is "okay" but I would like to view anything online to help me with this.
I've had the flu/cold for 5 days now and I know that part of my not "getting it" really well is due to that. Tomorrow aftgernoon (Tues) we have lab with ECG's and I need to understand it better.
The depolarization, repolarization thing is not clicking....... help!
Feb 22, '05
Here are some of the notes I have on this topic:
Explanation of figure 19.16:
1) P wave is produced when a signal from the SA node spreads through to the atria and depolarizes them. Atrial systole begins about 100 msec after the P wave begins, during the P-Q segment. It represents the time required for impulses to travel from the SA node to the AV node.
2) The QRS complex consists of a small downward deflection (S). It marks the firing of the AV node and onset of ventricular depolarization
(the complex shape of QRS is d/t different sizes of the two ventricles and different times req'd for them to depolarize)
Ventricular systole soon after the QRS complex in the S-T segment. Atrial repolarization
and diastole also occur during the QRS interval, atrial repolarization sends a relatively weak signal that is obscured by the electrical activity of the more muscular ventricles. The ST segment corresponds to the plateau in the myocardial action potential and thus represents a time during which the ventricles contract and eject blood.
3) The T wave is generated by ventricular repolarization immediately before diastole. The ventricles take longer to repolarize than to depolarise; The T wave is therefore smaller and more spread out than the QRS complex.
- typical ECG & diagram explain depolarization/repolarization, from Anatomy & Physiology by Saladin. K.
- lecture notes on depolarization/repolarization + ECH
It's a tough topic, but with a lot of studying you'll soon come to understand it. Hope this helps.
Last edit by blue eyes on Feb 22, '05