ECG Flashcards
Normal magnitude
10mm/mV
Normal speed
25mm/s
Calculate rate
Count QRS, x 6
Determining SR
-Each p wave followed by QRS
- Each QRS preceeded by p
- QRS regular
- PRi consistent
Normal PR
120ms-200ms
PR <120ms
Wolf Parkinson White - can cause re-entry tachycardias
A/w delta waves
PR >200ms (5 small sq)
1st degree heart block
QRS follows some, but not all, Pw
2nd degree heart block
Types of 2nd degree heart block
Mobitz Type 1 - gradual increase in PRi, finally missed QRS
Mobitz Type 2 - fixed PRi, regular droppings of QRS in a set ratio, e.g. 2:1 block
Which type of 2nd deg HB more likely requires pacing?
Mobitz Type 2
Pw and QRSc in no way linked
3rd deg HB, urgent pacing required
Best leads to determine axis
Lead 1 and aVF
Causes of L. axis deviation
LBBB
LVH
Old inf.MI
Pacing
LAFB
WPWs
Causes of R. axis deviation
RVH
PE
COPD
Old lat.MI
LPFB
NA channel blocker toxicity (e.g TCA OD)
WPWs
Causes of negative L1 & aVF
Hyperkalaemia
VT
Limb lead misplacement
Pw represents
atrial contraction
New onset AF can indicate
Sepsis
Thyrotoxicosis
Electrolyte abnormalities
Q waves are abnormal in
V1-3
Any other lead where Qw is large
Qw are normal in
III and aVR
Leads other than V1-3 as long as small
QRS duration
<120ms (3ssq)
Causes of wide QRS
Bundle branch block
Artificial pacing
Ventricular pacing
LBBB findings
RSR shape in V6 (‘M’)
Deep broad S in V1
LAD
STe in anterior leads
RBBB findings
RSR in V1
Wide, slurred S in V6
Axis likely normal
TWi V1-3
Inferior leads
II, III, aVF
Anterior leads
V1-V4
Septal leas
V1, V2
Lateral leads
I, aVL, V5, V6
Differences in STe: STEMI vs pericarditis
STEMI - Curving upward STE
PeriC- Curving downward STE
Possible presentation of posterior STEMI
Reciprocal change in anterior leads - STE changes only seen if add posterior leads
Causes of STDep
Digoxin
Hypokalaemia
Early signs in STEMI
Tw hyperacute - large and broad
ST depression
K+ abnormalities
Hypo - flattened Tw
Hyper - tall tented Tw, can cause VFib, flat Pw, widening QRS
QTc measured from…
ms from first downward deflection of Qw ro very end of Tw
QTc changes with HR
Shortens in tachy, lengthens in brady
Causes of prolonged QTc
Hypokalaemia
Hypocalcaemia
Hypomagnesaemia
Antipsychotics - lurasidone is best! Cloz, olanz, arip, risp and sulp all ok
Antidepressants - citalopram, SNRI and TCA all bad
Psychotropics - lithium, methadone
Antiarrhythmics - flecainide, amiodarone, sotalol
Antibiotics - erythromycin, clari, cipro
Antimalarials - chloroquine