ECG 2

Question 1

What 3 abnormalities can be detected by an ECG?

Answer 1

conduction - insulation issue
structural - hypertrophy compromises ability of heart to pump, change in cardiac axis
perfusion abnormalities - coronary artery blockage/narrowing leading to cell death

Question 2

What is the normal voltage and paper speed of an ECG?

Answer 2

V = 10ml/mV
speed = 25ml/s

Question 3

How does COPD affect the functioning of the heart?

Answer 3

harder to breathe
pulmonary hypertension
RV pumps harder leaving to a RAD

Question 4

Shortcut for determining HR?

Answer 4

300/number of big squares

Question 5

What is sinus rhythm?

Answer 5

P wave followed by QRS
regular rate  (even RR intervals)
normal speed (60-100bpm)

Question 6

What is sinus bradycardia?

Answer 6

rate regular but long
slow speed (56bpm)

• could be healthy but with big heart so increased SV and low HR to maintain adequate CO
• medication
• vagal stimulus (activation of PNS)

Question 7

What is sinus tachycardia?

Answer 7

rate regular (but short)
fast (107bpm)

- physiological response (secondary)
overactive adrenal gland
hyperactive SNS 
lower SV
blood loss (decreased VR)

Question 8

What is sinus arrhythmia?

Answer 8

irregular rate (variable RR intervals)
normal speed
RR interval changes with breathing cyle
NOT PATHOLOGICAL

Question 9

What creates a fuzzy trace?

Answer 9

EMR (noise)

Question 10

What is a trick for determining axis deviation?

Answer 10

Look at LEAD 1 and III
lead 1 positive and 3 negative indicates LAD

lead 1 negative and 3 positive indicated RAD

Question 11

What is atrial fibrillation?

supraventricular

Answer 11

no visible P wave
oscillating baseline (no isoelectric line) - atria contract asynchronously
irregular rhythm and slow rate
turbulent flow pattern increases clot risk (blood pools)

manage with oral anticoagulants
not so severe as atria are not essential for the cardiac cycle - passive filling maintains CO

Question 12

What is atrial flutter?

supraventricular

Answer 12

regular, saw tooth pattern in baseline (II, III, avF)
atria to ventricular beats in a 2:1 or 3:1 ratio or more
saw tooth not visible in all leads (has specific vector)

Question 13

What is first degree heart/AV block?

Answer 13

prolonged PR interval (>200ms)
slower AV conduction
regular ratio
most benign heart block - progressive disease of ageing

Question 14

What is second degree heart block?

Answer 14

Mobitz 1
gradual prolongation of PR interval until beat skipped
regular P wave and RR interval
regularly irregular

caused by diseased AV node
3:1 ratio of success to failure

Question 15

What is Mobitz II?

Answer 15

P wave regular - only some followed by QRS
No PR prolongation
regularly irregular
2:1

can rapidly deteriorate to 3rd degree heart block

Question 16

What is third degree/complete heart block?

Answer 16

non sinus rhythm 
P and QRS regular but no relationship
SAN 70BPM
AVM 50BPM
ventricular myocardium 30BPM

Question 17

What is ventricular tachycardia?

Answer 17

ventricle beat faster than can fill –> decrease CO
P wave hidden - dissociated atrial rhythm
regular shape and fast rate (100-200bpm)

at risk of deteriorating into fibrillation (cardiac arrest)
use defibrillator

Question 18

What is ventricular fibrillation?

Answer 18

asynchronous ventricular contraction
irregular HR (>250bpm)
heart cannot generate output (no filling)
at cardiac arrest

Question 19

What is ST elevation?

Answer 19

P wave visible, followed by QRS
regular rhythm, normal rate
ST segment elevated more than 2mm above isoelectric line

due to infarction (tissue death by hypoperfusion)

Question 20

What is ST depression?

Answer 20

P wave visible, followed by QRS
regular rhythm, normal rate
ST segment depressed more than 2mm below isoelectric line

caused by myocardial ischaemia (coronary insufficiency)