DSA 1: Normal ECG Flashcards
What does the information on EKG represent?
Heart’s electrical activity
What does the myocardium do when it is electrically stimulated?
Heart contracts
During the resting state, is the interior of every myocyte is positive or negative?
Negative
How is an influx of positive charges into a myocyte reflected on an EKG?
Upward deflection on EKG
What is the dominant pacemaker in the heart?
Where is it located?
SA Node
-upper posterior wall of right atrium
What does the P wave represent?
Atrial depolarization and contraction
What is the role of the AV node?
Conduct depolarization stimulus through fibrous AV valves to ventricles
Where does depolarization continue after AV node?
His bundles to right and left bundle branches
-rapidly conducting Purkinje fibers
What does the QRS complex represent?
Depolarization of ventricle and initiation of ventricular contraction
What does the T wave represent?
Ventricular repolarization
On the EKG, what segments show ventricular systole?
QRS to end of T wave (QT interval)
What is the role of free calcium inside myocytes?
Produces contraction
What ion is responsible for repolarization in myocytes?
Potassium
Why is conduction in the AV node slower compared to SA node?
Slow movement of calcium ions
A standard EKG has ___ limb leads and ___ chest leads.
6 limb leads
6 chest leads
