EKG lecture 1 highlights Flashcards
_______________ is the fundamental electrical event of the heart…results in + ions to cross the cell membrane
Depolarization
Repolarization usually occurs in the ________ direction as depolarization
opposite
What is the significance of the SA node?
Main electrical ‘generator’ for the heart.
Pacemaker cells are source of a “wave of depolarization” resulting in cardiac __________
systole
1) Repolarization results in the development of what?
2) Action Potentials can be recorded via what?
1) An Action Potential.
2) Surface electrodes resulting in an electrical tracing (EKG)
Each cycle of the cardiac cycle, contraction and relaxation, is initiated how?
An action potential that results in depolarization and repolarization (normally lead by SA node)
True or false: Pacemaker and conduction electrical activity not visualized on EKG
True; insufficient voltage to be recorded by surface electrodes
On an EKG:
1) What represents time?
2) What represents height?
1) Duration
2) Amplitude
Horizontal axis measures time; list the following:
1) 1 small square
2) 1 large square
3) 5 large squares
“memorize this”
1) 0.04 sec
2) 0.2 sec
3) 1 sec
Vertical axis measures voltage; list the following:
1) 1 small square
2) 1 large square
3) 2 large squares
“memorize this”
1) 0.1 mV
2) 0.5 mV
3) 1.0 mV
1) The P wave on EKG represents what?
2) The PR segment on EKG represents what?
1) Atrial depolarization/ contraction
2) Pause at the AV node
QRS complex:
1) If first deflection is downward = __________
2) First upward deflection is called what?
3) If there is a second upward deflection, what is this?
4) First downward deflection following an upward deflection is called what?
5) If entire complex is a downward deflection = __________.
1) Q wave
2) R wave
3) R’ (R-prime)
4) S wave
5) QS wave
First downward deflection of the QRS complex is called?
Q wave
List the parts of depolarization on an EKG
1) Atrial = P wave
2) AV node pause = PR segment
3) Ventricular = QRS wave
List the 2 refractory periods on an EKG
1) Atrial = PR segment
2) Ventricle = ST segment
Atrial repolarization is buried in QRS depolarization, but ventricular repolarization = __________
T wave
1) Define PR interval
2) Define PR segment
1) P wave + flat line connecting to the QRS complex
2) Flat line from end of P wave to start of QRS complex
Define:
1) QRS duration
2) ST segment
3) QT interval
1) QRS duration
2) Flat line connecting end of QRS to beginning of T wave
3) QRS + ST segment & T wave
