ECG Flashcards
What is the speed of an ECG
25mm/sec
How is rate calculated
300/number of 5mm squares per R-R interval
Describe a normal P wave
<0.25 mV
upright in II III and aVF
Describe a normal QRS complex
between 0.06-0.10s
narrow or wide
Sinus rhythm
Normal P and QRS
One P followed by one QRS
regular rhythmn
no discernible P wave and irregular QRS complexes is indicative of..
Atrial fibrillation
What arrthymia gives a sawtoothed appearance
atrial flutter
what arrthymia would present with normal QRS but absent P waves
junctional tachycardia
what causes a bifid P wave
p-mitrale
left atrial hypertrophy
what causes a peaked P wave
p-pulmonale
right atrial hypertrophy
what is the normal length of the PR interval
0.12 - 0.2s
time between atrial and ventricular depolarisation
measured from beginning of P to beginning of Q
Describe a normal Q wave
<0.04s and <2mm
How would ventricular conduction defects present
long QRS complex
what is indicated by low voltage of a Q wave
hypothyroidism, COAD, myocarditis, pericarditis and pericardial effusion
What indicates left ventricular hypertrophy on an ECG
R wave of greater than 25mm in V5
sum of S wave in V1 and R wave in V5/6 >35mm
What indicates right ventricular hypertrophy on an ECG?
Dominant V1 R wave
T wave inversion in V1-3 or V4
Deep S wave in V6
What might cause a significant Q wave
acute MI
Pericardial effusion on shown lead III
What is a normal QTc interval and how is it calculated?
QT/sqRR
0.38-0.42 s
Prolonged QT interval can be caused by
acute Myocardial ischaemia
myocarditis
brachycardia
which part of the ECG is usually isoelectric
ST segment
what is indicated by ST elevation?
infarction
what is indicated by ST depression?
ischaemia
in what limb leads is it abnormal for the t wave to be inverted?
I, II and V4 to V6
what effects does digoxin have on the ECG
T wave inversion
ST segment sloping depression
what is a normal axis of the heart?
between -30 and 90
what happens in left axis deviation
- 30 - -90
- ve QRS deflection in II and III
what happens in right axis deviation
+90 to +180
-ve deflections in I
describe the 3 ECG stages of an acute MI
T wave peaking followed by inversion
ST segment elevation
appearance of new Q waves
how does an anterior infarction present on an ECG
Q waves in V2-4
Inverted T waves in leads V4-6
how does an anterolateral infarction present on an ECG
Q waves in leads I,II, AVL, V3-5
Raised ST in V2-6
how does an inferior infarction present?
Q waves in II and aVF
depressed ST in aVL and V6
how does a pulmonary embolism present?
large S wave in I
deep Q in II
inverted T in III
hyperkalaemia ECG presentation
tall tented T
widened QRS
hypokalaemia ECG presentation
small T waves, prominent U
hypercalcaemia ECG presentation
short QT interval
hypocalcaemia ECG presentation
long QT interval, small T waves
