Clinical Electrocardiography Flashcards
why is an ECG used? (3)
+ve’s of ECG (3/4)
what does the ECG consist of? how many leads (remember leads= views) 3 3 6 polar?
colour of electrode and where to put it (rhyme)
- investigate symptoms
- diagnose disease eg. hypertension
- Arrhythmia analysis
- cheap
- quick
- not invasive
- fundamental assessment
3 limb leads: I,II,III -> bipolar
3 augmented limb leads : aVF, aVL, aVR -> unipolar
6 around chest looking in a horizontal plane
Ride - Red - Right arm
Your - Yellow - Left arm
Green - Green - Left ankle
Bike - Black - Right ankle (neutral/ earth electrode)
escape rhythms:
SA
AV
Pirkinje
how many seconds in one strip?
5 big squares=
2 rules for counting HR
normal sinus rhythm determined by: (2)
SA- 60-100 bpm
AV- 40-60 bpm
Pirkinje- 20- 45 bpm
1 strip= 10s
5 big squares= 1s
count number of R waves
or
count number of squares between 2 R waves and divide 300 by that number (good for tachycardia)
sinus rhythm:
- normal P wave followed by regular QRS
- regularity by looking at R-R distances
Atrial Fibrillation
what is it and how does it usually occur?
seen on ECG by: (2)
type of rhythm= …. because
mini-circuits in atria caused by scarring in atria
seen as:
No clear P waves
wobbly line
-irregularly irregular QRS complexes as impulses are hitting the AV node at random times
Atrial Flutter
what is it and what is it caused by?
whats seen on ECG? (1)
ratios represent?
Macro-circuit around right atrium caused by extra conduction tissue near AV valve
on ECG seen as Saw Tooth Motion
3:1 block -> every third AP from atria reaches ventricles
2:1 block
The Heart Block Story
Normal conduction: (2)
First Degree
what’s happening? (4)
Second Degree Type 1 aka Wanke bach
what’s happening? (4)
Second Degree Type 2
what’s happening? (4)
Third Degree (3)
Normal Conduction:
QRS always after P wave
0.2s between P wave and QRS or less
First Degree: P wave present QRS always present but late same every beat >0.2s (5 small squares
Second Degree Type 1 aka Wanke bach:
- P wave present
- QRS becomes later and later until doesn’t show
- PR interval increases each time until QRS dropped
- two P waves consecutively
Second Degree Type 2
- P wave present
- sometimes QRS present sometimes not- unpredictable
- seen by random P waves without QRS
- need pacemaker
Third Degree
- Regular P waves at one rate
- QRS regular at another rate, both on completely separate schedule
- usually their escape rhythms so QRS slower
Broad complex tachycardia
what is it?
why? (2)
whats seen on ECG? (2)
what is it?
ventricles have mini-circuit and dictate HR
why? (2)
- scar tissue (from MI) some cardiomyocytes are dead and others partially dead -> one pathway quicker
- causes a re-entry circuit around scar
whats seen on ECG?
big broad QRS complex
v high HR (150 bpm)
The Alphabet:
P wave
larger amplitude=
double peak=
PR interval
normal time=
prolonged=
QRS complex
normal time=
inc. amplitude=
Broad QRS=
ST segment
if elevated could mean…
depressed could mean…
T waves
inversion could be
morphology could be due to (2)
QT interval
starts and ends where?
normal=
The Alphabet:
P wave
larger amplitude= pulmonale or right atrial enlargement
double peak= mitrale or left atrial enlargement
PR interval
normal time= 3-5 small squares (200ms)
prolonged= First Degree Heart Block
QRS complex
normal time= <120ms
inc. amplitude= LV hypertrophy
Broad QRS= bundle branch block
ST segment
if elevated could mean…STEMI (if above iso-electric line)
depressed could mean… ischaemia
T waves inversion could be- ischaemia morphology could be due to: - K+ too low ->flat and prolonged T wave - K+ too high -> early MI!
QT interval
starts and ends where?
stater of Q wave- end of T wave
normal= <440ms
Axis
Refers to overall electrical direction within heart
look at which leads?
left axis deviation seen as: (2)
right axis deviation seen as: (2)
look at which leads?
I or II
left axis deviation seen as: (2)
I- very +ve
III- very -ve
right axis deviation seen as: (2)
I- more -ve
III- more +ve
