ECG

Question 1

Normal HR for sinus rhythm

Answer 1

60-100bpm

Question 2

P wave axis for sinus rhythm

Answer 2

Upright in leads 1 and 2 and inverted in aVR

Question 3

QRS complex length for sinus rhythm

Answer 3

<100ms

Question 4

Normal PR interval

Answer 4

120-200ms and constant

Question 5

How does the QT interval vary with HR

Answer 5

Inversely proportional

Question 6

Main ECG change on STEMI

Answer 6

ST elevation

Question 7

Anterior STEMI ECG

Answer 7

Precordial leads V1-6 ST elevation
Reciprocal ST depression in inferior leads 3 and aVF

Question 8

Lateral STEMI ECG

Answer 8

ST elevation in leads 1 aVL and V5-6
Reciprocal ST depression in inferior leads 3 and aVF

Question 9

High lateral STEMI ECG

Answer 9

ST elevation localised to leads 1 and aVL

Question 10

Inferior STEMI ECG

Answer 10

ST elevation in leads 2 3 and aVF
Reciprocal ST depression in aVL
Progressive development of Q waves in 2 3 aVF

Question 11

ECG NSTEMI findings

Answer 11

Regional ST depression
T wave inversion or flattening
Dynamic or new Q or T wave changes

Question 12

Define atrial fibrillation

Answer 12

Dysrhythmia characterised by disorganised atrial activity and contraction resulting in an irregularly irregular ventricular response

Question 13

Key ECG features of AF (5)

Answer 13

• no p wave
• irregularly irregular rhythm
• no isoelectric baseline
• variable ventricular rate
• QRS<120 ms (unless existing BBB or accessory pathway)

Question 14

ECG features of complete heart block

Answer 14

Severe bradycardia due to no AV conduction
Complete AV dissociation - independent atrial and ventricular rates

Question 15

What is left bundle branch block?

Answer 15

Conduction delay which means impulses travel first via RBBB to RV and then to LV via the septum (r to l instead of l to r). This reverses septal activation so Q waves eliminated

Question 16

Normal conduction through bundle branches

Answer 16

Impulses travel equally through R and L bundles, septum activated from left to right and formation of small Q waves in lateral leads

Question 17

ECG findings for LBBB (4)

Answer 17

• Broad monophasic R waves in lateral leads (1, aVL, V5-6)
• deep S waves in right precordial leads (V1-3)
• QRS> 120ms
• No Q waves in lateral leads

Question 18

What is right bundle branch block?

Answer 18

Delayed activation of right ventricle causing a secondary R wave

Question 19

ECG findings in RBBB (3)

Answer 19

• QRS> 120 ms
• RSR’ pattern in V1-3
• wide slurred S wave in lateral leads (1, aVL, V5-6)

Question 20

What is ventricular fibrillation

Answer 20

• shockable arrest rhythm
  Ventricles attempt to contract at rates of up to 500bpm, rapid and irregular activity results in loss of cardiac output
  Prolonged VF results in asystole

Question 21

ECG findings in VF (4)

Answer 21

• chaotic irregular deflections of varying amplitude
• no identifiable P waves, QRS complexes or T waves
• rate 150-500bpm
• amplitude decreases with duration

Question 22

ECG findings in VT ( 5)

Answer 22

• regular, broad complex tachycardia
• uniform QRS complexes in each lead
  MAY
• very broad complexes (>160ms)
• AV dissociation
• extreme axis deviation

Question 23

What is sinus arrhythmia?

Answer 23

Normal phenomenon commonly seen in young healthy people. HR varies due to change in vagal tone during respiratory cycle

Question 24

ECG findings in sinus arrhythmia

Answer 24

• variation in P-P interval of more than 120ms
• P-P interval gradually lengthens and shortens in cyclical fashion
• normal P waves
• constant PR interval

Question 25

Sinus bradycardia

Answer 25

HR<60bpm

Question 26

Sinus tachycardia

Answer 26

HR >100bpm

Question 27

Atrial flutter vs atrial fibrillation

Answer 27

AFib is irregular atrial contraction, atrial flutter is regular atrial activity but more often than ventricles

Question 28

Atrial flutter ecg findings (5)

Answer 28

-Narrow complex tachycardia - atrial activity ~300bpm - loss of isoelectric baseline - sawtooth inverted waves in 2,3, aVF - upright in V1 may resemble P waves

Question 29

Atrial ectopics ECG findings

Answer 29

- abnormal p wave followed by normal QRS - may not be conducted

Question 30

First degree AV Block ecg

Answer 30

PR>200ms

Question 31

2nd degree AV block (mobitz 1, wenckebach)

Answer 31

Progressive prolonging of PR until p wave is dropped

Question 32

What is SVT?

Answer 32

Any tachydysrhythmia originating above the bundle of his. Includes regular atrial, irregular atrial and regular AV tachycardia

Question 33

Atrioventricular re entry tachycardia

Answer 33

Form of SVT arising in patients with accessory pathways. Can be orthodromic (through av then accessory) or antidromic (through accessory then AV)

Question 34

AVRT vs AVNRT

Answer 34

avrt has an anatomical reentry circuit, in avnrt there is a functional reentry within AV node