1. Chest pain- ECG basics and interpretation Flashcards Preview

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Flashcards in 1. Chest pain- ECG basics and interpretation Deck (38)
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1
Q

Basics:

What is the P wave

A

atrial depolarisation

2
Q

Basics:

what is the PR interval

A

time taken for electrical activity to move between atria and ventricles

3
Q

Basics:

what is the QRS complex

A

depolarisation of the ventricles

4
Q

Basics:

what is the ST segment

A

the time taken between depolarisation and depolarisation of the ventricles

5
Q

Basics:

what is the T wave

A

ventricular depolarisation

6
Q

Which ECG leads represent the inferior view of the heart

A

II
III
aVF

7
Q

which ECG leads represent the anterior aspect of the heart

A

V3

V4

8
Q

which ECG leads represent the septal aspect of the heart

A

V1

V2

9
Q

which ECG leads represent the lateral aspect of the heart

A
I
aVL
V5
V6
(aVR)
10
Q

ECG interpretation:

If you are given an ECG what are the first things that you would check

A

Name on the ECG
date on the ECG
the settings are 25mm/sec, 10mm/mv

11
Q

ECG interpretation:

How do you work out the rate

A

300/number of big squares between two R waves

or count the number of R waves in the 10 second strip and multiple by 6

12
Q

ECG interpretation:

How do you know the ECG lead is in normal sinus rhythm

A

sinus rhythm means there will be a P wave between 3-5 squares

13
Q

ECG interpretation:

how do you know if the axis are normal

A

leads I, II, III should all have positive deflections

14
Q

ECG interpretation:

When looking at the QRS complex how do you know if it is broad or narrow

A

from beginning of Q wave (or R wave if there is no Q) should be less than 3 small squares

15
Q

ECG interpretation:

What would be suggested if the QRS is broader than 3 small squares

A

either the rhythm is originating in the ventricles or there may be a conduction issue (ie a bundle branch block)

16
Q

ECG interpretation:

how do you know if the cardiac axis is normal

A

If leads I and II are both positive then the axis is normal
(if lead I is positive and lead I is negative then probably LAD)
(if lead I is negative and lead II is positive then probably RAD)

17
Q

ECG interpretation:

what are you looking at with the Q waves and what is pathological Q wave

A
  • Q wave is the first downwad deflection before an R wave (R wave is first upward deflection)
  • pathological if more than 1 square wide
  • pathological if more than 2 squares deep (except in leads III & aVR)
  • pathological if seen in chest leads V1-V3 as no Q waves are usually present in these leads
18
Q

ECG interpretation:

how do you know if there is a LBBB

A

broad QRS complex ie greater than 3 small squares
deep S wave in V1
no Q wave in V5/6

19
Q

ECG interpretation:

if LBBB is present then what is it not possible to do

A

make any further diagnosis of the ECG

20
Q

ECG interpretation:

how do you know if there is a RBBB

A

broad QRS complex ie greater than 3 small squares
RSR (2 peaks) in V1
Slurred S wave in lateral leads I, V5, V6

21
Q

ECG interpretation:

what do normal T waves look like

A

upward in all lead except aVR (where everything is weird), V1 and sometimes V2

22
Q

ECG interpretation:

what should the ST segment look like

A

isoelectric with the rest of the ECG baseline and some deviation of more than 1mm above or below is abnormal

23
Q

ECG interpretation:

what would ST depression mean

A

the heart muscle isn’t dying but it is hurting for oxygen (ischemic endocardium)

24
Q

ECG interpretation:

what would ST elevation mean

A

the heart muscle is dying and this is a cardiac schema which needs to be treated immediately
Can see T wave inversion as well

25
Q

What is atrial fibrillation (Afib)

A

there is no organised signal between the SAN and AV node which causes atrial spasming

26
Q

what does atrial fibrillation look like on an ECG (Afib)

A
  • there is an irregularly irregular rhythm (look at the distance between the R-R interval)
  • no distinct P waves
27
Q

What is supraventricular tachycardia (SVT)

A

the abnormal heat beat stats at or above the Av node
the heartbeat is above 100bpm at rest
may be asymptomatic but also may have paliptations and chest pain

28
Q

what does supra ventricular tachycardia (SVT) look like on an ECG

A
  • Regular rhythm with a very high rate

- No clear P waves

29
Q

What is ventricular tachycardia (Vtach)

A

rapid heart heart beat that arises in the ventricles

caused by irritation by hormones, low O2, stretch
caused also by scars in myocardium

30
Q

how is ventricular tachycardia diagnosed on an ECG

A
  • broad QRS complex (more than 3 small squares)
  • no clear P waves
  • high rate above 100
31
Q

what is ventricular fibrillation

A

ventricles loose the ability to contract and circulate blood to rest of the body therefore person will be unconscious

won’t be able to feel a pulse

will have course squiggly lines on ECG

32
Q

name some risk factors for Vfib and Vtach

A
  • Irritable ventricular cells (CAD and electrolyte abnormalities such as high K+ or low Ca2+
  • Scar tissue (heart attack and cardiomyopathy which is disease of the heart tissue and can be caused by infection, genetic disorders and CAD)
  • Electrocution
33
Q

what would atrial flutter look like on an ECG

A

saw-tooth appearance of P waves

34
Q

Complications post MI:

what are the 3 main problems with the hear post MI

A

decreased contractility
electrical instability
tissue necrosis

35
Q

Complications post MI:

why is decreased contractility a problem

A

get pathological low blood pressure as LV can’t pump enough blood to the rest of the body leading to decreased coronary vessel perfusion

can lead to ischemia, cariogenic shock and a ventricular thrombus may form

36
Q

Complications post MI:

why is electrical instability a problem

A

lead to arrhythmias

37
Q

Complications post MI:

what happens is the papillary muscles becomes necroses

A

then the caudate tendinea can’t ensure the valves don’t invert

38
Q

Complications post MI:

how does cardiac tamponade occur

A

necrosis of ventricle therefore it ruptures into the pericardium