Flashcards in EKG Deck (121):
Where is the current EKGs measure?
in the ventricle, there is a zone of + resting and a zone of - excitation
which way does a vector point
towards the positive side
Mean electrical vector
the sum of the indiv. instant. vectors; ECG records this
4th ICS, 2 cm right of sternum
4th ICS, 2 cm left of sternum
5th ICS, left midclavicular
5th ICS, left anterior axillary line
left midaxillary line
What is the oddball lead?
aVR (all negative)
bipolar limb leads
I, II, III
what is Einthoven's triangle?
Leads I, II, III
axis of lead
the direction from - to + of a lead
Mean QRS axis
average direction of MEV during ventricular depolarization
where should you look at for quick axis diagnosis?
Leads I and AVF
+90 to 0/-30* (both positive)
left axis deviation
0/-30* to -90* (I positive, AVF negative)
extreme right axis deviation
-90* to 180* (both negative)
right axis deviation
+90 to 180 (I negative, AVF positive)
dimensions of EKG
small (1x1 mm); lg (5x5 mm)
time--> small (0.04 sec); lg (0.2 secs)
voltage--> sm (0.1 mV); lg (0.5 mV)
What leads show a normal + P wave?
I, II***, AVL, AVF, V5, V6
What leads show a normal - P wave?
What leads show a normal BIP P wave?
What leads show a normal variable P wave?
V2, V3, V4
Which leads show a normal septal Q wave?
I, AVL, V5, V6***
What leads show a normal R wave?
I, II, III, AVL, AVF, V5***, V6
What is the J point?
origin of ST segment at end of QRS
What leads show a normal S wave?
AVR, V1, V2
What leads show a normal transition QRS wave?
What leads show a normal - T wave?
What leads show a normal + T wave?
III, AVL, AFV, V2-V6
What leads show a normal BIP/- T wave?
What leads show no T wave?
How long is PR Interval?
How long is QRS Interval?
<= 0.10 sec
How long is QT Interval?
How long is corrected QT interval?
<= 0.44 sec
anterior apical leads
hi left lateral leads
lo left lateral leads
II, III, aVF
anterior septal leads
1st deflection is down (sm=n, lg=infarct)
1st deflection is up
second up deflection
1st down deflection after up deflection
1 down deflection w/o R present
current towards electrode
current away from electrode
perpendicular to electrode
repolarization of cells
T wave changes
sensitive to electrolytes, ischemia, & drugs
follows T wave, represents repol of Purkinje
Heart Rate Method 1
60/R-R interval (rhythm strip X6)
HR Method 2
wherever 2nd QRS falls is HR
HR Method 3
count # in 3 sec interval, mult. by 20
What is PR interval?
onset of P wave to onset of QRS
What is QRS interval
from beg. to end of complex
What is QT interval
from beginning of Q to end of T
What is corrected QT interval
When does Lt Axis Dev. occur?
inferior wall MI
When does Rt Axis Dev. occur?
Acute Right Heart Strain (PE)
Rt Atrial Enlargement
Inc. P-wave + amplitude in Lead II
Lt Atrial Enlargement
Inc P wave - amp and duration in V1
Which side does the QRS axis deviate to in VH?
Which leads do you spot VH in?
Which leads do you spot AE?
R>S in lead I; Right Axis Deviation
etiology pulmonary & congenital
Lt Axis Deviation;
S in V1 plus R in V5/V6 => 35 mm
OR R in aVL >11 mm OR R in I >15 mm
etiology HTN, valvular disease
Main difference between AE and VH
duration change in AE (Lt)
axis shift in VH
Bundle branch blocks
myocyte-myocyte spread of conduction; QRS WIDENS
widened QRS; RSR' in V1
prom. S in lead V6
absent R, prominent S in V1
absent Q, broad R in V6
Where does left anterior fascicle run
ant., superior, lat portion of LV
where does left posterior fascicle run
post., inferior, med. LV
why don't hemiblocks have widened QRS
purkinje fibers bridge gaps
left axis deviation
Q in I and wide/deep S in III
right axis deviation
deep S in I and Q in III
Inc R in V1&2 with NO Axis Dev.
Q wave in II, III, AVF
Extensive Anterior MI
Q V5-V6, I, aVL
Transient Myocardial Ischemia
T wave inversion in V2-V6 (negative)
Acute ST segment Elev MI
elevated over infarct,
deep over opposite side
Acute Non-ST segment Elev MI
***acute POC thrombus***
ST depression over infarct
normal EKG with HR <60 bpm
ischemia, cardiomyopathy, meds, metabolic promblems
Sick Sinus Syndrome
dizziness, syncope, confusion
common in pts with AFib
No P Waves
Junctional and Ventricular
Junctional escape rhythm
arise from AV node/bundle of His
normal QRS complex
rate 40 to 60 bpm
Ventricular Escape Rhythm
depolarized past His
WIDENED QRS, 30-40 bpm
1* AV Block
increased PR interval (>0.2 sec)
2* AV Block
P waves with no QRS
Type I 2* AV block
progressive Inc. in PR Interval until QRS skipped and then restarts
Type II 2* AV block
severe blockage of bundle of His/Purkinje
sudden loss of QRS (widened when present)
3* AV block
"complete heart block*
no relation btwn P & QRS
if @ AV, normal QRS with 40-60
if @ His, wide QRS and dec. rate
3* AV Block @ His
wide QRS and dec. rate
3* AV block @ AV
normal QRS with 40-60
100-180 bpm, normal EKG otherwise
Atrial Premature Beats (APB)
not related to SA! P-wave abnormal. early
2 A:1 V
A 350-600 bpm/ V 140-160
Paroxysmal Supraventricular Tachycardia
sudden onset/termination with rate of 140-250 bpm
most common in adults
NO P-wave, normal QRS
no change in wave or widened QRS
Retrograde P waves visible
ventricular pre-excitation syndrome
decreased PRT interval (<0.12 secs)
slurred, widened QRS
widened QRS, inverted T
series of =>3 VPBS
Torsades de Pointe
polymorphic, early afterdepol