ECG Flashcards
what leads supply the septal heart
V1, V2
what leads supply the anterior heart
V3, V4
what leads supply the apical/lateral heart
V5, V6
what leads supply the lateral heart
L1, aVL
what leads supply the inferior heart
L2, L3, aVF
How much is each small square in ECG worth
0.04s
How much is each large square in ECG worth
0.2s
What leads does the LAD supply
V1-V4
What occurs if the LAD is blocked
HF
because the LAD suppies the powerhouse of the heart
What leads does the LCx supply
L1, AVL + V5, V6
what artery supply leads L2, L3, AvF
+ SAN, AVN
RCA»_space; obstruction of this artery leads to heart block
How must you present an ECG (order of things)
- Patient details + indictions + prior ECG
- Rate
- Rhythm
- Axis
- P wave
- PR interval
- BBB
- QRS complex
- T wave
- ST segment
- QT interval
How do you count rate
number of R waves on rhythm strip x 6
OR
300/ number of large squares betweeen R waves
How do you assess rhythm
P waves before every QRS? > sinus
regular? if not, is it IRregularly irreg or regularly irreg
What can cause a regularly irreg rhythm
heart block second degree
what causes an irreg irreg rhytm
SVT (AF, AFlut)
VF, torsade
What is a common cause of a bradicardia
Heart block (esp 1st degree, which is regular)
How do you determine AXIS
look at LI and LII:
- if they Leave > LEFT AXIS DEVIATION
- if they Reach for each other > RIGHT axis deviation
causes of right axis deviatino
normal in children and skinny adults
lateral MI
RVH
causes of left axis dev
LBBB
inferior MI
pacemaker rhythm
(LVH does NOT cause Left axis deviation because even as it enlarges the rhythm keeps going the normal direction)
What causes an abnormal P wave
Tall peaked P wave - Pulmonary HTN, cor pulmomale
How long is a prolonged PR interval?
> 0.2 seconds
What is a first degree HB
PR interval prolonged but constant
What is second degree HB
Mobitz T1: progressive prolongation of PR, drops, cycle restarts
Mobitz T2: occasional P not followed by QRS at a ration (e.,g. 2:1, 3:1)
What is third degree HB
complete HB with P and QRT occurring independently
What is left an right BBB
look at V1 and V6
Left BBB: WiLLiaM
Right BBB : MaRRoW
What abnormality can be detected in QRS compex?
WIDE >0.12 s
due to BBB, pacmaker, hyperkalaemia
What causes an inverted T wav?
post MI
What causes a tall and tented T wav
hyperacyte MI (early stemi)
hyperkalaemia
what are causes of ST elevation
Full thickness MI
prinzmetal angina, coronary spasm
Pricarditis
What causes ST depression
Partial thicknss MI (NSTEMI)
unstable angiina
digoxin doxcity
what are causes of prolonged QT interval
congential channelopathies
meds e.g. SSRI
metabolic e.g. hypokalaemia, hypocalcaema
How does ventricular tachy present
WIDE QRS (broad complex tachy)
Rate > 120
REGULAR
Ventricular fibrillation on ECG
irregular broad complex tachy
extremely IRREGULAR
HR 300-600
how does PE present on ECG
usually normal
sinus tachycardia
RBBB due to R heart strain
S1Q3T3 (S wave in lead I, Q wave and inverted T wave in lead III)
how does hyperkalaemia present on ECG
tall and tented T wave
flattened P wave
Broad QRS
what condition presents with a short PR interval and why?
WPW
HOw does WPW preseent on ECG
short PR interval
delta wave (slurred upstroke of QRS complex - due to accessory pathway early firing)
what do you see in a posterior MI
tall R waves in V1, V2
when should you worry a QT is prolonged?
when >0.5
