Interpretation of ECG Flashcards Preview

Medicine MD3001 cardiovascular system > Interpretation of ECG > Flashcards

Flashcards in Interpretation of ECG Deck (43):
1

how is a regular rate on an ECG calculated?

300/number of big squares per R-R interval

2

what is a normal rate?

60-100 bpm

3

what is a sinus rhythm?

-normal P waves
-normal QRS complexes
-one P wave per QRS complex
-regular rhythm

4

how is atrial fibrillation seen on an ECG trace?

-no discernable P waves
-irregular QRS complexes

5

how is arterial flutter seen on an ECG trace?

-p waves seen at a rate of 300 per minute
-p waves have a saw toothed appearance

6

what is Junctional tachycardia? how is junctional tachycardia seen on ECG?

-impulses arriving from AV node
-normal QRS complexes yet absent P waves

7

what is ventricular tachycardia?

-after 2 sinus beats rate increases to 150 bpm
-QRS complexes become broad and T waves are difficult to identify

8

what is a P wave? What is its normal form on an ECG?

-time for atrial depolarisation
-less than 0.25 mv should be upright in 2,3 and aVF

9

what is P-mitrale?

-bifid P wave
-L atrial hypertrophy

10

what is P pulmonale?

-peaked P wave greater than 0.25 mv
-R atrial hypertrophy

11

what is the PR interval? what is the normal range?

-time between atrial and ventricular depolarisation
-0.12 s-0.2 s

12

what does an abnormal length PR interval mean?

prolonged interval implies delayed AV conduction hence a 1st degree heart block

13

what is QRS complex? what is the normal range?

-time for ventricular depolarisation
-normally is less than or equal to 0.12s

14

what is normal Q wave?

less than 0.04s and less than 2mm in depth

15

what is an abnormal QRS complex? What is it indicative of?

-greater than 0.12s
-ventricular conduction defects- left or right Bundle Branch Block

16

what does it mean if the voltage of the QRS complex is less than 5mv?

-hypothyroidism
-COAD
-Myocarditis
-precarditis and pericardial effusion

17

how is L ventricular hypertrophy seen on an ECG?

R wave in V5 greater than 25mv

18

how is R ventricular hypertrophy seen on ECG trace?

dominant R wave in V1 or deep S wave in V6

19

what features define a significant Q wave?

-interval greater than 0.04s
-depth greater than 2mv

20

what does an abnormal Q wave in lead 3 indicate?

Pulmonary embolism

21

what is QT interval?

-measured from start of Q to end of T
-ventricular depolarisation then repolarisation

22

how is corrected QT calculated?

QTc= QT/ square route of RR interval

23

what is normal range for the QT interval?

0.38-0.42 s

24

why is the corrected QT interval used?

any change in heart rate alters QT interval and the heart rate is not constant

25

what can cause prolonged QT interval?

-acute myocardial ischaemia
-myocarditis
-bradycardia
-head injury
-hypothermia
-urea and electrolyte imbalance
congenital
-drugs

26

what is the the ST segment?

time from end of ventricular depolarisation to start of ventricular repolarisation

27

what is a normal ST segment?

isoelectric

28

what does ST elevation indicate? what defines ST elevation?

-1mm in 2 adjacent limb leads
-infarction

29

what does depression of ST segment indicate?

ischaemia

30

what are T waves representative of?

ventricular repolarisation

31

where are T waves most likely to be inverted?

aVR and V1

32

where is it abnormal for T waves to be inverted? What is this indicative of?

-lead 1 or 2 and V4-V6
-ischaemia or infarction

33

what effects does digoxin have on T waves?

-T wave inversion
-St segment slopping depression

34

what 3 changes happen to ECG trace in Acute MI?

-T wave peaking followed by T wave depression
-ST segment elevation
-appearance of new Q waves

35

how is an anterior infract identified on an ECG?

-sinus rhythm
-Q waves in leads V2-V4
-inverted T waves leads V4-V6

36

how is an anterolateral infarct seen in an ECG?

-sinus rhythm
-Q waves in leads 1, 2 aVL
-raised ST segments V2-V6

37

how is an inferior infract seen on an ECG?

-sinus rhythm
-Q waves leads 3 and aVF
-depressed ST segment in aVL and V6

38

how is a posterior infarct identified from an ECG?

V1- ST segment depression and tall R wave

39

How can a pulmonary embolism be identified from an ECG?

-large S wave in lead 1
-deep Q wave in lead 3
-inverted T wave in lead 3

40

what are the features of hyperkalaemia on an ECG?

-Tall, tented T wave
-widened QRS

41

what are the ECG features of hypokalaemia?

-small T wave
-prominant U wave

42

what is the features on an ECG of hypercalcaemia?

short QT interval

43

what are the 2 features on an ECG identifying hypocalcaemia?

-long QT interval
-small T waves

Decks in Medicine MD3001 cardiovascular system Class (44):