ACCURATE SOLUTIONS | LATEST UPDATE .
P wave represents - correct Answers -Atrial depolarization
Axis of p wave - correct Answers -0 to +75° (down and left)
How long a p wave should last - correct Answers -0.08-.11 seconds
Tp wave represents - correct Answers -atrial repolarization (usually not visualized on an EKG; wave
orientation opposite of P wave)
PR segment represents - correct Answers -electrical depolarization thru AV node, His bundles,
bundle branches, and Purkinje system
describe where the PR segment should be - correct Answers -usually on the baseline. normal if
depressed by <0.8 mm
PR interval represents - correct Answers -time period of all events from SA node impulse to moment
of ventricular depolarization
PR interval should last _____ sec. - correct Answers -0.11-0.20 seconds
QRS complex represents - correct Answers -ventricular depolarization
QRS complex time range - correct Answers -0.06-0.11 seconds
axis of QRS complex - correct Answers --30° to +105° ; down and left
significance of q wave - correct Answers -Not always present
If present, benign or dead myocardial tissue
,Pathological if width ≥0.03 s or height ≥1/3 height of R wave
Benign q waves often found in leads I, AVL and V6 = "septal Qs"
Intrinsicoid deflection is found where on the EKG? - correct Answers -In leads that don't contain a q
wave, it's the period from the beginning of the QRS complex to beginning of negative down-slope of
the R wave.
Intrinsicoid deflection represents... - correct Answers -Amount of tie electrical impulse takes to
travel from Purkinje system in endocardium to surface of epicardium.
Intrinsicoid deflection time ranges - correct Answers -≤0.035s in right precordial leads (V1 & V2)
≤0.045s in left precordial leads (V5 & V6)
ST segment represents... - correct Answers -Neutral period for the heart
It's the time that the myocardium is maintaining contraction in order to push blood out of ventricles
How should the ST segment appear on an EKG? - correct Answers -Usually along baseline.
Can vary up to 1 mm from baseline in limb leads of normal pts.
Can vary up to 3 mm in right precordials of some pts (left ventricular hypertrophy or early
depolarization pattern).
Any ST elevation in a symptomatic pt should be considered significant of MI injury or infarction until
proven otherwise!!
T wave represents - correct Answers -ventricular repolarization
How should a T wave appear? - correct Answers -The deflection (+ or -) that occurs after ST segment
Should begin in SAME direction as QRS complex
Should be asymmetrical w. 1st part rising or dropping slowly and 2nd part steeper
QT interval represents? - correct Answers -All events of ventricular systole.
Goes from beginning of QRS complex to end of T wave
QT interval should be shorter than...? - correct Answers -1/2 of the preceding R-R interval
, QTc interval formula - correct Answers -QTc = QT + 1.75(ventricular rate - 60)
QTc interval normal duration - correct Answers -0.410 seconds
lengthened QTc > 0.419 seconds
U wave - correct Answers -Cardiac event represented is unknown.
Small, flat wave sometimes seen after T wave, before P wave, and deflects in same direction as T
wave.
Clinical importance: usually benign. could potentially be a sign of hypokalemia.
Normal Sinus Rhythm (NSR) - correct Answers -Rate: 60-100 bpm
Regularity: Regular
P wave: present
P:QRS ratio: 1:1
PR interval: normal
QRS width: normal
Grouping: none
Dropped beats: none
Sinus Arrhythmia - correct Answers -Rate: 60-100 bpm
Regularity: *varies w/ respiration*
P wave: normal
P:QRS ratio: 1:1
PR interval: normal
QRS width: normal
Grouping: none
Dropped beats: none
This rhythm represents normal respiratory variation, becoming slower during exhalation and faster
upon inhalation (b/c inhalation increases venous return by lowering intrathoracic pressure). Note