EKG Flashcards
Where is the current EKGs measure?
ECM
Cardiac Dipole
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
V1
4th ICS, 2 cm right of sternum
V2
4th ICS, 2 cm left of sternum
V4
5th ICS, left midclavicular
V5
5th ICS, left anterior axillary line
V6
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
aVR
-150*
aVF
+90*
aVL
-30*
I
0*
II
+60*
III
+120*
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
normal axis
+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)
horizontal reading
time–> small (0.04 sec); lg (0.2 secs)
vertical reading
voltage–> sm (0.1 mV); lg (0.5 mV)
P-wave
atrial depolarization
What leads show a normal + P wave?
I, II***, AVL, AVF, V5, V6
What leads show a normal - P wave?
aVR
What leads show a normal BIP P wave?
III, V1
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?
V3, V4
What leads show a normal - T wave?
AVR
What leads show a normal + T wave?
III, AVL, AFV, V2-V6
What leads show a normal BIP/- T wave?
V1, V2
What leads show no T wave?
I, II
How long is PR Interval?
0.12-0.20 sec
How long is QRS Interval?
<= 0.10 sec
How long is QT Interval?
0.35 sec
How long is corrected QT interval?
<= 0.44 sec
anterior apical leads
V3, V4
hi left lateral leads
I, aVL
lo left lateral leads
V5, V6
inferior leads
II, III, aVF
anterior septal leads
V1, V2
Q wave
1st deflection is down (sm=n, lg=infarct)
R wave
1st deflection is up
R’ wave
second up deflection
S wave
1st down deflection after up deflection
QS
1 down deflection w/o R present
+
current towards electrode
-
current away from electrode
biphasic
perpendicular to electrode
T wave
repolarization of cells
T wave changes
sensitive to electrolytes, ischemia, & drugs
U wave
follows T wave, represents repol of Purkinje
Heart Rate Method 1
60/R-R interval (rhythm strip X6)
HR Method 2
300-150-100-75-60-50
wherever 2nd QRS falls is HR
HR Method 3
count # in 3 sec interval, mult. by 20
*irregular HR
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
QT/sqrt(R-R)
When does Lt Axis Dev. occur?
inferior wall MI
LAFB
LVT (occ.)
When does Rt Axis Dev. occur?
RV Hypertrophy
Acute Right Heart Strain (PE)
LPFB
Rt Atrial Enlargement
Inc. P-wave + amplitude in Lead II
Pulmonary etiology
Lt Atrial Enlargement
Inc P wave - amp and duration in V1
mitral etiology
Which side does the QRS axis deviate to in VH?
hypertrophied side
Which leads do you spot VH in?
I, AVF
Which leads do you spot AE?
II, V1
Rt VH
R>S in lead I; Right Axis Deviation
etiology pulmonary & congenital
Lt VH
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
RBBB
widened QRS; RSR’ in V1
prom. S in lead V6
LBBB
widened QRS
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
LAFB
left axis deviation
Q in I and wide/deep S in III
LPFB
right axis deviation
deep S in I and Q in III
posterior MI
Inc R in V1&2 with NO Axis Dev.
RCA affected
inferior MI
Q wave in II, III, AVF
RCA
anteroseptal MI
Q V1-V2
LAD
Anterioapical MI
Q V3,V4
LAD
Extensive Anterior MI
Q V1-V6
LCA
Anterolateral MI
Q V5-V6, I, aVL
CFX
Transient Myocardial Ischemia
T wave inversion in V2-V6 (negative)
Acute ST segment Elev MI
elevated over infarct,
deep over opposite side
ionic leak
Acute Non-ST segment Elev MI
acute POC thrombus
ST depression over infarct
Sinus Bradycardia
normal EKG with HR <60 bpm
ischemia, cardiomyopathy, meds, metabolic promblems
athletes
Sick Sinus Syndrome
intermittent SB
dizziness, syncope, confusion
common in pts with AFib
Escape Rhythms
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
benign
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
Sinus tachycardia
100-180 bpm, normal EKG otherwise
Atrial Premature Beats (APB)
not related to SA! P-wave abnormal. early
Atrial Flutter
100-350 bpm
2 A:1 V
atrial fibrillation
A 350-600 bpm/ V 140-160
no p-waves
Paroxysmal Supraventricular Tachycardia
sudden onset/termination with rate of 140-250 bpm
AVNRT
most common in adults
NO P-wave, normal QRS
orthodromic AVRT
no change in wave or widened QRS
Retrograde P waves visible
antidromic AVRT
widened QRS
ventricular pre-excitation syndrome
“wolff-parkinson-white”
decreased PRT interval (<0.12 secs)
slurred, widened QRS
VPB
widened QRS, inverted T
VT
series of =>3 VPBS
100-200 bpm
Torsades de Pointe
(VT)
polymorphic, early afterdepol
VFib
morbidity increased, cessation of cardiac output
