ecg interpretation Flashcards
-The electrocardiogram (ECG)is a representation of the — of the cardiac cycle
-Each event, such as atrial/ventricular contraction, has a distinctive – on an ECG
-The waveform of a normal heartbeat is called — since it arises from the –
-Abnormalities in the electrical activity of the heart can help to diagnose – and— diseases.
electrical events
waveform
sinus rhythm
sinoatrial node
cardiac and systemic
placing the ecg leads:
An ECG has – physical electrodes
Vectors are calculated from the – electrodes to generate the standard — lead ECG used in clinical practice
Chest leads: - physical electrodes
V1 — — intercostal space (ICS), – of the —
V2 — — ICS, just – of the –
V3 — midway between – and —
V4 — — ICS on the —
V5 — — , — line, same level as –
V6 — — , - — line, same level as — and —
-Limb leads: – physical electrodes
– electrodes for – limb leads
Right and left arm
Right and left leg
-Vectors are calculated from —leads the – — limb is a grounding lead
10
limb
12
6
4th
right of stream
4th
left of stream
v2 v4
5th ICS on midclaviualr line
anterior axial line
v4
mid-axially line
v4 v5
4
4
6
3
right lower
understanding ECG graph paper:
X-axis represents time:
Rate of tracing generally seen on ECG as — mm/sec = — boxes per second
Large box = – sec(–mm)
Small box = — sec(–mm)
Entire rhythm strip (lead II) is — seconds
Y-axis represents voltage:
Large box = – mV
Small box = – mV
25
5 large boxes
0.2 ( 5 mm)
0.04 (1mm)
10 seconds
0.5 mv
0.1 mv
check graph slide 7
1- p wave:
P wave represents —
Duration: < — ms or — squares
2- PR interval:
Represents the time taken for excitation to spread from the — node across the — and down to the — via the —
Normal PR interval is — ms i.e. — , – squares
3- QT interval:
-The time from the start of the — to the end of the —
Represents the time between — and —
-The QT intervalshortensat — heart rates
-The QT intervallengthensat — heart rates
QT interval is often corrected for — (QTc)
-A prolonged QT is associated with an increased risk of —
atrial depolarisation
<120 , 3 small
SA
atrium
ventricular muscle aka bundle of HIS
120-200
three to five small squares
q wave
t wave
ventricular depolarisation n repolarisation
fasrer
slower
heart rate
ventricular arrhythmias
4- ST segment:
TheST segmentis the — , —
section of the ECG between the – ofhe – wave (the – point) and the— of the – wave
The ST Segment represents the interval between — and —
Interpreted relative to the preceding TP segment
5- T wave:
- — of ventricles
- — deflection in — and —
flat , isoelectric
end
s
J point
beginning
t wave
ventricular depolarisation and repolarisation
repolarisation
-ve
V1 and aVR
The cardiac axis represents the overall — of —
Under normal circumstances the — is the most abundant cardiac muscle, therefore normal cardiac axis is directed – and slightly to the —
The – leads are used to determine the cardiac axis
Abnormal cardiac axis can indicate –
direction of cardiac depolarisation
left venticule
downward
left
limb
pathology
determining the axis:
The cardiac axis can be determined from leads —-
A lead is positive if its most prominent deflection is — the baseline
A lead is negative if its most prominent deflection is — the baseline
-LAD = left axis deviation
-RAD = right axis deviation
I , II , III
above
under
( pls check slide 14-23)
ECG- rate interpretation:
The rhythm strip (lead II) of an ECG represents cardiac aECGctivity over —
Therefore, the heart rate over 10 seconds is the number of QRS complexes ( – contractions) on the rhythm strip
The heart rate per minute can then be calculated by — the — complexes in — by —
In this example 11 QRS complexes in 10s = 66bpm
10 seconds
ventiuclar
multiplying
QRS
10 seconds
6
determining the rate from single cardiac cycle:
One large box on ECG = – seconds
Therefore, one minute will comprise — large boxes (60 seconds divided by 0.2 seconds)
To calculate the heart rate in one minute divide — by the number of — boxes in a single cardiac cycle
For ventricular rate the – wave is used
The small boxes can be utilized in the same way
One small box on ECG = — seconds
Therefore, one minute will comprise — small boxes (60 seconds divided by 0.04 seconds)
To calculate the heart rate in one minute divide — by the number of — boxes in a single cardiac cycle
( info: The normal heart rate is 60-100 beats / minute)
0.2
300
300
large
r wave
0.04
1500
1500
small
-Arrhythmia is anything other than normal —
-This may be an abnormal heart — and/or abnormal pathway — in the heart
-The normal conduction pathways in the heart are — . Damage to these pathways or conduction through abnormal pathways generally results in — conduction
-Cardiac rhythm is usually defined as – or — by examining the — between— complexes
sinus rhythm
rate or conduction
fast
slow
regular or irregular
spaces
QRS ( check slide 33)
Is there a P-wave before every QRS?
Normal sinus rhythm = always a P wave — every QRS complex. The electrical impulse is arising from the —
No discernible P waves = —
Sawtooth pattern of p-waves = —
before
arterial fibrillation
artrial flutter
What is the PR interval?
A prolonged PR interval suggests — ( — conductance from SA node to AV node)
What is the QRS morphology?
A — (normal) QRS suggests a rhythm arising from the atria
A — QRS suggests a rhythm of ventricular origin
Is the QT interval normal?
A prolonged QT interval can cause —
AV heart block
prolonged
narrow
broad
ventricular arrhythmias
- atrial arrhythmia:
1- Sinus tachycardia/bradycardia – — , — complex QRS with — before all QRS complexes
2- Atrial fibrillation – — , — complex QRS with no discernible —
3- AV heart block – — , — QRS complex with prolonged — - ventricular arrythmias:
1- Ventricular tachycardia – – , — & – complex QRS with no discernible —
2- Ventricular fibrillation – – , — QRS complexes
regular , narrow
p wave
irregular , narrow
p wave
regular , narrow
prolonged PR
regular, fast , broad
p wave
chaotic , broad
ST segment abnormalities:
Causes of elevated ST segment:
—- , —
Causes of depressed ST segment
— , —- , — abnormalities
T- wave abnormalities:
1- Peaked:
— , —
2- Inverted
— , — , —
1- Acute transmural infarction,
Pericarditis
2- Non-ST elevation MI , ishcemias , electrolyte abnormalities
peaked: ‘Hyperacute’ Infarction ,
Elevated potassium
inverted : Myocardial infarction
Ischaemia
Pulmonary embolism
summary:
The ECG is an electrical representation of the —
Abnormal electrical activity in the heart can help to make the correct diagnosis
Interpretation of the ECG requires a — approach
Start with the – , followed by — (regular / irregular), look for – waves, followed by abnormalities of the other waves and intervals
cardiac cycle
systemic
rate
rhythm
p wave
