ecg Flashcards
what does P wave indicate?
atrium depolarization
Q wave?
septum depolarization
R wave?
ventricle depolarization
S wave?
Signals going up from the ventricles
T wave?
ventricle depolarization ?
P-R interval
the AV node holding the signal for 0.13 seconds or (0.12-0.20)
QRS complexes
ventriclar depolarization less than 0.12 seconds
ST segment
end of depolarization and beginning of repolarization
its also the isoelectric period of depolarized ventricle
QT interval
time between the whole depolar and the whole repolar
It also indicates the whole AP period
RR interval
time between Peak of each QRS complex which represent the beats
U wave
represent Purkinje fibers repolarization
whats the normal charge of the cell?
inside is negative and outside is positive
how is upward or downward deflection formed in ecg
if the charge going to a similar charge is going to form upward if going to opposite will form downward for example
+ going toward + electrode –> upward deflection
+ charge going toward - electrode –> downward deflection
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whats the difference between monophasic action potential and ECG?
in monophasic AP you measure the AP directly from the cell
in ecg you put on the skin so its far
Since the MAP is directly from cell so it produces higher voltage compared to ECG
In ecg theres no potential is recorded in ecg when ventricular muscle is completely polarized or depolar
what are the types of ECG leads?
-Limb leads
- Chest leads
what are the two types of limb leads
Bipolar standard limbs ( 2 ELECTRODES )
Augmented unipolar limb leads ( one electrode )
what are the leads of bipolar standar limbs
lead 1
lead 2
lead 3
whats einthoven triangle law?
if you have any 2 leads you can get the third one
lead 1 + lead 3 = lead 2
what are the augmented bipolar leads?
AVr –> right
AVf–> Foot
AvL —> Left
what view is given by each lead?
the positive electrode is the eye,
lead 1 –> the positive electrode is on the left arm so looks at the heart from the left and lateral side
lead 2 –> positive electrode is on the left leg so looks at the heart from below
lead 3 –> positive electrode is on the left leg so looks at the heart from below like lead 2
AVr–> + electrode is on the right limb so looks like at the heart from the right side
AVL –> + electrode is on the left limb –> looks at the heart from the left lateral side like lead 1
AVF –> + electrode is on the lower limb so looks at the heart from below like lead 2 and 3
what are the electrodes you need for chest lead?
- YOU NEED LIMB ELECTRODE on Left arm and right arm and left leg ,
- you need chest electrodes ON THE CHEST, V1 AND V2 ON THE BASE
V5 , V6- apex of the heart
what are the location of the chest leads?
V1- RIGHT 4th intercostal space
V2- LEFT 4th intercostal space
V3- 5TH RIB
V4- 5th intercostal space
V5- ANTERIOR AXILLARY FOLD
V6- MID AXILLARY FFOLD
what plane does the limb leads show the heart?
frontal, coronal plane
what plane does the chest leads show the heart at?
transverse plane
which leads show downwarD?
AVR , V1 , V2 , V3
what are the angle of axis?
lead 1 = 0
lead 2 = 60
lead 3 = 120
AVF = 90
aVL = -30
AVR = 210
what is the normal axis?
-30 - 100 or 59 degrees
whats right axis deviation ?
when the axis is more than 100
what could cause right axis deviation?
any condition that causes right ventricle hypertrophy :
1- Right ventricle hypertrophy
2- left posterior fascicular block
3- acute right heart strain ( pulmonary embolism ) the block due to embolism will cause right v to work more = hypertrophy
Pulmonary valve stenosis
what is left axis deviation?
when the axis is less that -30
what could cause left axis deviation?
any condition that causes left v hypertrophy :
1- left ventricle hypertrophy
2- left anterior fascicular block
3- inferior border MI
Left branch bundle block, aortic stenosis
how to know if theres deviation?
1st look for AVr to see if its downward or nah ( this is to make sure that leads are place properly if its not downward then theres a mistake in placement
1- look at lead 1 and 2 if both are upward –> normal if not then
If lead 1 is downward = right axis deviation
If lead 2 is downward = left axis deviation
physiological left axis deviation is seen when lead is both upward and downward
whats a current of injury?
cardiac abnormality that causes part of the heart to remain partially depolarized or fully depolar all the time
what could cause a current of injury?
mechanical trauma
infection
ischemia and mi
describe sinus tachycarida?
heart rate is more than 100 but its normal and its due to sympathetic activity
describe sinus bradycardia
heart rate is less than 60 but the ecg is normal and its due to parasympatehtic activity
describe paraxysmal supraventricular tacycardia
SUDDEN increase of heart beats 150-250 AND ITS FROM TIEHR ATRIM ECTOPIC FOCUS OR AV ectopic fci
OCCUR IN YOUNG HEALTHY INDIVIDUAL AND THEY GROW OUT OF IT AFTER ADOLSCENCE
describe paraxysmal ventricular tachycardia
sudden fast heart beats of 150-250 beats BUT THIS TIME IS DUE TO VENTRICULAR ECTOPIC FOCI
Dangerours and is probably due to ischemia
describle first degree block
prolonged P-R interval is more than 0.2 ( normal is 0.12 to 0.2)
second degree block
random blockage of an signal , and prolonged pr interval
mobitz 1 and mobitz 2
third degree block
no relation at all
describe atrial fibrillation
multiple atrial beats to MULTIPLE ECTOPIC FOCUS discharging rapidly 350-450 beats
- either small P or no P cuz it will be neutralized by the ectopic focus firing at the same time
usually due to atrial enlargment due to valve diseas ( mitral stenosis and regurg ,
describe ventriclar fibrillation
most serious arrhythmia ,
Cardiac go beserk due to ectopic foci in ventricles and no coordination and NO CO
Caused by either electrical cardiac shock and ischemia of heart muscles and conductive system
whats a large square and small square in the horizenta axis
small box = 0.04 seconds
large box is 5 small boxes = 0.04 x 5 = 0.2 seconds
whats a large square in y axis
0.5 mL
how to determine heart rate quickly from ecg?
look for rr interval and how many boxes are between each r waves,
use the 300 rule, divide 300 by the number of LARGE boxes of the rr
if there are 3 boxes then heart rate is 300 / 3 = 100
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