ECG Flashcards
Speed of paper
25mm/s
Large square
0.2 seconds
Small square
0.04 seconds
How to calculate rate
300/ no. of large squares between R-R interval
OR
QRS complexes in rhythm strip x 6
Causes of sinus tachycardia >100/min
- anaemia
- anxiety
- exercise
- Pain
- Fever
- Sepsis
- Hypovolaemia
- Heart failure
- PE
- Pregnancy
- Hyperthyroid
- Thiamine deficiency
- CO2 retention
- Autonomic neuropathy
- Sympathomimetics- caffiene, adrenaline,nicotine
Causes of sinus bradycardia <60/min
- Physical fitness
- Vasovagal attacks
- Sick sinus syndrome (sinus node dysfunction)
- Acute MI (Esp. inferior)
- Drugs- beta blockers, digoxin, amiodarone, verapamil
- Hypothyroid
- Hypothermia
- Increased ICP
- Cholestasis
Normal axis
-30(avL) to +90(aVF)
Right axis deviation
+90 to +180
Left axis deviation
-30 to -90
Left axis deviation causes
- Left anterior hemiblock
- Inferior MI
- VT from LV focus
- WPW syndrome - more common types
- LVH
Right axis deviation causes
- RVH
- PE
- Anterolateral MI
- Left posterior hemiblock (rare)
- WPW - less common types
Absent P waves
- AF
- SA block
- Junctional AVN rhythm
- hyperkalaemia
Peaked P waves
P pulmonale- Right atrial hypertrophy
Bifid P waves
P mitrale- mitral stenosis
Pseudo P pulmonale
hypokalaemia
PR interval
start of P wave to start of QRS
- 0.12 - 0.2s ( 3-5 small squares)
- Prolonged= AVN block (e.g. heart blocks)
- Short= fast AV conduction through accessory pathway (WPW
QRS
- 0.12
- > 0.12= ventricular conduction defect- BBB
- Large QRS= VH
2 criterias for LVH on ECG
- Height of S in V1 and R in V6 - if >35 mm then LVH
OR
- Largest R/S in limb leads >20mm
Where is Q wave normally seen?
Lateral leads:
V5, V6, a VL and I
anywhere ellse is abnormal
Q wave in an abnormal lead is indicative of?
- post MI
QRS - delta wave
WPW syndrome
QTc duration
0.4 seconds
Start of QRS to end of T
Causes of prolong QTc
- Hypothermia
- Acute MI
- Myocarditis
- Bradycardia (AV block)
- Head injury
- U & E balance - hypo K, Ca, Mg
- Congenital :Romano-Ward, Jervell-Lange-Neilson syndrome
- Drugs: sotalol , amiodarone, macrolides (erythromycin), quinidine , antihistamines, phenothiazines, tricylics
Downsloping ST segment
DIGOXIN
- reverse tick sign
Where is T wave normally inverted?
aVR, V1 +/- V2, never V2 alone, occasionally V2/V3
Peaked T wave
Hyperkalaemia
Which leads is T wave inversion abnormal?
I, II, V4-V6
Flattened T wave
Hypokalaemia
T inversion in V1-V3
- normal (p and children)
- RBBB
- PE
T inverson in V2-V5
- Subendocardial MI
- HOCM
- SAH
- Lithium
T inversion in V4-V6
- Ischaemia
- LVH
3, LBBB
Hypothermia ECG changes
J waves
Tall late R waves in V1
Hyperkalaemia ECG changes
- tall peaked t waves
- Broad QRS
- Sinusoidal ECG
- small/absent P waves
- Increased PR interval
- V.fib , asystole
Hypokalaemia ECG changes
- Flat T waves
- ST depression
- long QT
- ventricular dysarrythmias
PE ECG changes
1) normal ECG
2) SINUS Tacchycardia
- tachycardia
- RAD
- R. ventricular strain
- AF
- S1 Q3 T3
R. heart strain signs
S1 Q3 T3
S wave in lead 1
Q wave in lead III
Inverted T wave in lead III
AF ecg signs
Absent P waves
QRS irregularly irregular
Atrial flutter ecg signs
Sawtooth line of atrial depolarisation
Regular QRS complexes
Variable degree of AV conduction
Nodal rhythm
Normal QRS
P waves absent or occur just before or within QRS
Ventricular ryhtm
QRS complexes >0.12 with P waves following them
1st and 2nd degree heart block causes
- Normal variant
- Athletes
- Sick sinus syndrome
IHD
Acute carditis
Drugs (digoxin and beta blockers)
3rd degree complete heart block causes
- idiopathic (fibrosis)
- congenital
- IHD
- Aortic valve calcification
- Cardiac surgery/ trauma
- Digoxin toxicity
- Infiltration (abscess, granuloma, tumours, parasites)
