Quick Basics Flashcards
PR Interval Duration
Where: Start P-wave to start of Q/R
Time: 0.12 - 0.20 secs
QRS Complex Duration
Where: Start Q to end of S
Time: 0.08 - 0.10 secs
WIDE = 0.12 sec/120ms (LESS THAN 3 Small BOXES)
ST-Segment Duration
Where: End of S to the start of T
What: All the ventricular myocardium is depolarized
QT Interval Duration
Where: QT Interval
Time: 0.35 - 0.45 secs
QTc - (OT corrected)
- Male > 0.46 sec abnormal
- Female > 0.44 sec abnormal
Inferior View of Heart
II
III
avF
Septal View of Heart
V1
V2
avR
Anterior View of Heart
V3
V4
Lateral View of Heart
I
avL
V5
V6
Absolute Refractory
Cells do not respond to any stimulus
Effective Refractory
Cells do not respond to conducted (cell-to-cell) stimuli, but will respond to other stimuli (cause arrhythmias)
Relative Refractory
Cells respond to LARGER-than-normal stimulus
Supernormal Refractory
Cells respond to weaker - than - normal stimulus
Big Box Duration
Width (time)
- 5 mm = 0.20 seconds
Height (amplitude)
- 5 mm = 5 mV
Small Box Duration
Width (time)
- 1 mm = 0.04 seconds
Height (amplitude)
- 1 mm = 1 mV
P-Wave
Atrial Depolarization
PR Segment
AV Node holding Action Potential from conducting
PR Interval
The time between atrial depolarization and ventricular depolarization
0.12 - 0.20 sec (>0.20 sec/200ms is considered delayed/prolonged)
Supraventricular activity
Q Wave
Basal Septum Depolarization
(0.04 sec or less)
R Wave
Ventricular Depolarization
S Wave
Basal Ventricular Depolarization
ST Segment
Ventricles are positively charged and there is no movement of ions
T Wave
Ventricular Repolarization
Ventricles are turning back to negative charges
U Wave
Repolarization of the Purkinje Fibers
(Not normally seen)
Origin of narrow (< 0.11 secs) QRS Complex
Supraventricular
Narrow (normal) QRS Complex
0.08 - 0.11 seconds
(or less than 0.11)
Wide QRS Complex
0.12 and above
QT Interval
When: Beginning of the QRS Complex to the end of the T Wave
How Long: < 0.44
What: Covers the entire ventricular activity.
Which Segment is used to determine if the ST segment is elevated or depressed?
TP Segment
P wave begins and end at the ________
Isoelectric Line
Q wave begins and end at the ________
Isoelectric Line
R wave begins and ends at the ________
Isoelectric Line
S wave begins and ends at the ________
Isoelectric Line
ALL wave begins and ends at the ________
Isoelectric Line
Q-Wave Morphology
q = _________
Q = _________
q = Physiologic
Q = PATHologic
Q-Wave Morphology
Q = represents what pathology
Pathologic Q waves are a sign of previous myocardial infarction.
They are the result of the absence of electrical activity.
A myocardial infarction can be thought of as an electrical ‘hole’ as scar tissue is electrically dead and therefore results in pathologic Q waves.
Q-Wave Morphology
Q = How do you recognize pathologic Q Wave?
- > 0.04sec or 40 ms (1 mm) wide.
- > 25% of depth of QRS complex.
- Seen in leads V1-3.
PR Interval Represents
Wave goes over the atrium and through the AV node and ends just before it activates the ventricles to depolarize
PR segment represents
Depolarization of the AV node.
It’s a flat line because the wave is not strong enough to be recorded on the voltmeter.
Q wave
Ventricular Septal Depolarization
R wave
Resultant or major ventricular muscle depolarization. The resultant vector is directed downward and leftward.
S Wave
Basal Ventricular depolarization
The base of the ventricles connects to the atria.
ST segment
All the ventricular myocardium is depolarized.
T wave represents
Ventricular repolarization
QT interval
- It covers the entire ventricular activity.
- Captures the beginning of ventricular depolarization through the plateau phase to the ventricular repolarization.
