Flashcards in EKG Deck (32)
What are the steps of EKG interpretation?
6. Infarction / Ischemia
How do you determine rate?
Measure R-R intervals or count the # of complexes and multiply by 6
How do you measure rate using the RR interval?
use the 300 – 150 – 100 – 75 – 60 – 50 - 40
What are the intervals we measure?
PR, QRS, Qtc
What is the normal PR interval?
0.12 - 0.20 seconds
What does one "itty-bitty" box count for? what about one big box?
itty-bitty box = 0.04 seconds
big box = 0.20 seconds
What is the normal QRS interval?
0.06 - 0.10 seconds
What is the normal QTc interval?
0.30 - 0.46 seconds or as long as the Qt interval is less than half the preceding R-R interval
What is normal axis?
between -30 and 90
Where is the axis if lead I is positive and lead II is positive?
Normal axis! -30 to -90
Where is the axis if lead I is positive and lead II is negative?
left axis deviation! -30 to 270
Where is the axis if lead I is negative and lead II is positive?
right axis deviation! 90 to 150
Where is the axis if lead I is negative and lead II is negative?
no mans land! 150 to 270
PR interval more than 0.20 seconds with 1:1 conduction
1st degree AV block
PR interval lengthens followed by completely blocked P wave
2nd degree AV block type 1
PR interval stays the same, P waves are intermittently blocked
2nd degree AV block, type 2
P waves are completely blocked, QRS originates independently
3rd degree AV block
Right atrial hypertrophy
P wave in any limb lead is more than 2.5 mm
P wave in V1 is biphasic and the initial portion is the largest
Left atrial hypertrophy
P wave in lead II is notched with > 0.04 sec between peaks
P wave in V1 is biphasic and the terminal portion is the largest with usually a negative deflection
Right ventricular hypertrophy
Right axis deviation AND R wave in V1 is more than 7mm tall
Left ventricular hypertrophy
Cornell criteria: R wave in aVL + S in V3 = > 24 in men or > 20 in women
Any R + S in precordial leas >45mm
R wave in V5 more than 26mm
R wave in aVL at least 12 mm (most specific)
T waves biphasic with or without ST depression
QRS greater than or equal to 0.12 sec
Broad R waves in I, V5 and V6
- ST depression and T wave inversion in these leads
-large S wave in V1/V2
-possible left axis shift
Does having LBBB affect any other diagnosis?
hypertrophy and infarct
QRS equal to or more than 0.12 sec
rsR' in V1 and V2, typically second R larger
Diffuse Upward Concave ST segment elevation except for aVR with no reciprocal ST depressions
Tall, narrow, peaked T wave with possible QT shortening
K+ = 5.5 - 6.5 mEq/L
flattened wide P waves, widened QRS
K+ = 6.5 - 7.5 mEq/L
Loss of P waves, very wide QRS, VT, VF, asystole
K+ > 7.5 mEq/L