EKG I & II Flashcards
Depolarization of the atria in response to SA node triggering is represented by the ____
P wave
Delay of the AV node to allow filling of the ventricles is represented by the ____
PR interval
Ventricular repolarization is represented by the ____
T wave
Depolarization of the ventricles is represented by the ____.
(time from AV node thru Purkinjie fibers)
QRS complex
____ is the beginning of ventricle repolarization, and should be flat
ST segment
P wave can be inverted in lead ___
aVR
What is the length of a normal P wave
< 0.12 seconds
or <3 boxes
A broad or notched P wave in leads II or V1 is a sign of ______
left atrial enlargement
Peaked P waves in leads II or V1 is a sign of ______
right atrial enlargement
An ectopic inverted P wave is a sign that the site of origin of contraction is from ___
lower atria or AV junction
An ectopic upright P wave is a sign that the site of origin of contraction is from ___
high in the atria
Normal duration of the PR interval is ___ seconds or ____ boxes.
< 0.20 seconds 1 large (5 small) boxes
Normal duration of the QRS complex is ____ seconds or ____ boxes.
< 0.12 seconds
< 3 small boxes
Q wave should be < __ boxes in amplitude and < __ box in duration
< 2 amplitude
< 1 duration
Abnormal (larger) Q waves indicate ____
prior or current MI
RSR’ indicates a ____
bundle branch block
ST elevations in specific leads indicate ____, while diffuse ST elevations indicate ____.
- MI
- pericarditis
ST depressions indicate ____
myocardial ischemia
Peaked T waves may suggest ____ or ____
- MI
- hyperkalemia
Inverted T waves may suggest ______
- cardiac ischemia
- LVH
- hypokalemia
- digitalis administration
Normal QT interval should be ____ seconds
< 500ms (0.5 sec)
QT interval shortening can be due to ____
hypercalcemia
Prolonged or shortened QT intervals both increase risk of ____
ventricular tachycardia (Torsades)
U waves are more common in ___
young athletes
Large U waves can be due to
- hyperkalemia
- thyroid disease
- medication effects
What are the sets of numbers used in the triplicate method?
300-150-100 75-60-50
What are the steps of interpreting an EKG?
- Age
- Rate
- Axis
- Rhythm
- Evaluate following:
- P wave, PR interval
- Q wave depth, QT prolongation
- R wave - progression, QRS width
- ST - elevate/depression
- T wave - peaked/inverted
When determining axis, left thumb should be lead ___ and right thumb should be lead ___.
Lead I = left
aVF = right
Which lead should you look at if both Lead I and aVF are negative?
Lead II
If (+), normal
If (-), LEFT axis
When determining axis, 2 thumbs up means ____
normal axis
When determining axis, left up and right down means
left axis deviation
When determining axis, left down and right up means
right axis deviation
What are some causes of LAD?
LVH, emphysema, hyperkalemia, Atrial septal defect, obesity
What are some causes of RAD?
RVH, chronic lung disease, PE
- can be normal in kids and tall thin adults
A wide QRS indicates that something is slowing the electrical current through the ventricles in the _____.
Purkinje fibers
True or False: RVH is the most common hypertrophy
FALSE - LVH more common
What is the criteria used to identify LVH?
R in V5 or V6 is >35 mm (>7 boxes)
S in V1 or V2 is >30 mm ( >6 boxes)
What are the steps for evaluating for RVH?
- evaluate for RAD first
- If RAD and R wave in V1 >7mm, then RVH
