Electrocardiogram Flashcards
What is an ECG
Electro_Cardio_gram
Deivice used on the surface of the body that can detect the electrical changes associated with stimulation of the atria and ventricles on the body’s surface
What does the contraction of the cardiac muscle result from?
a series of electrical potential changes that move rapidly through the heart (depolarization)
what is the cardiac muscle stimulated by
Intrinsic mechanisms
What does the INTRINSIC Conduction System do/ ensure?
Ensures that the cardiac muscle within the heart depolarizes in a SEQUENTIAL manner (atria to ventricles) so the heart can beat as a coordinated unit.
Components of the Intrinsic Conduction System
- Sinoatrial (SA) Node
- Atrioventricular (AV) Node
- AV Bundle (Bundle of HIS)
- Right and Left Bundles
- Purkinje Fibers
Location of Sinoatrial (SA) Node and nickname and speed
Within the right atrium, inferior to the superior vena cava opening
fastest intrinsic rate, and controlls the other parts of the conduction system. Called the hearts “Pacemaker”
Location of Atrioventricular (AV) Node
Base of Right Atrium, may take over if the SA NODE is not working properly
Location of AV Bundle (Bundle of HIS)
Interventricular septum
Location of Right and Left Bundles
Interventricular Septum
Location of Purkinje Fibers
Ventricular walls
ECG Electrodes are called
“Leads” that are places on the surface of the body on locations where it is easiest to pick up electrical signals from the heart
ORDER: 1 2 3 4
Depolarization
Contraction
Repolarization
Relaxation
P
P-Q segment
QRS Complex
- Atrial depolarization
- Atrial plateau, occures in sarcolemma od cardiac muscle cells when they are cotracted
- Ventricular depolarization
S-T segment
T
Ventricular plateau, when the muscles are being contracted
-Ventricular repolarizaiton
P-R Interval
Q-T Interval
Time it takes for depolarization to spread from SA node to AV node(.12-.2 seconds )
Time it takes for ventricles to depolarize and repolarize (.2-.4 seconds)
