ECG

Question 1

Which leads show : Septal view of the heart

Answer 1

V1 + V2

Question 2

Which leads show lateral view of the heart?

Answer 2

I , AVL, V5, V6

Question 3

Which leads show an anterior view of the heart?

Answer 3

V3, V4

Question 4

Which leads show inferior view of the heart?

Answer 4

II, III and AVF

Question 5

Which lead is at 0 degrees

Answer 5

I

Question 6

Which lead is at 60 degrees?

Answer 6

II

Question 7

Which lead is at +90 degrees?

Answer 7

AvF

Question 8

Which lead is at +120 degrees?

Answer 8

III

Question 9

Which lead is at -150 degrees?

Answer 9

aVR

Question 10

ECG - 1 small square

Answer 10

1mm / 40 ms

Question 11

ECG : 1 large square

Answer 11

0.5cm / 200 ms

Question 12

How is the rate calculated?

Answer 12

QRS (over 10 secs) x 6 = HR Big squares between R-R / 300

Question 13

What is the definition of sinus rhythm?

Answer 13

Action potential originated from the SA node

Question 14

How is sinus rhythm seen on an ECG?

Answer 14

• P waves up right: Lead II
• Inverted P wavesin: Lead AVR
  Each P waves looks the same in the same lead

Question 15

What is normal cardiac axis?

Answer 15

• • Lead II
• • aVF

Question 16

What is RAD in ECG?

Answer 16

• Lead III +
• aVF +
• aVR + (extreme axis dev)

Question 17

What is LAD in ECG?

Answer 17

• • aVF
• • Lead I

Question 18

What is the definiton of cardiac axis?

Answer 18

Overall direction of electrical activity in the heart

Question 19

What are the causes of L. axis deviation?

Answer 19

*Left bundle branch block
*Inferior MI
*Physiological } minor LAD in obese people

Question 20

What is the definition of the PR interval?

Answer 20

atrial depolarisation and contraction

Question 21

What is the ECG range of PR interval?

Answer 21

• 120 - 200m/s
• 3-5 small squares

Question 22

What is the defintion of WPW syndrome?

Answer 22

Accessory pathway allows for conduction of electrical impulses into the ventricle at a site other than the AV node.

Question 23

What are the ECG features of WPW syndrome?

Answer 23

• Short P-R interval : <120 m/s, AV node usually delays impulse to allow the ventricles to complete contracting but this accessory pathway bypasses the AV node
• Delta wave ‘slurred upstroke’ of the QRS complex

Question 24

What is first degree heart block/

Question 25

What is T1 mobitz - 2nd degree heart block?

Answer 25

* progressive lengthening of PR interval, * one non conducted P wave, next conducted beat has a shorter PR interval

Question 26

What is 3rd degree Heart block? (3)

Answer 26

- No relationship between P wave and QRS complex Regular P waves - none are conducted by the AVN - Broad QRS - ectopic beats

Question 27

What is the management of AV block?

Answer 27

1. 1st degree HB and Mobitz type 1 - usually do not require treatment as long as the patient is assymtpmatic 1. Mobitz type 2 and complete heart block (3rddegree) require permanent pacemaker

Question 28

What is T2 mobitz - 2nd degree heart block?

Answer 28

R-R interval is constant occasional non conducted P wave - in variable or set ration

Question 29

What is the pathophysiology behind LBBB?

Answer 29

1. Blocked L. bundle branch 2. Heart depolarised from Right bundle branch to left 3. Electrical activity travels from right to left 4. Tall R waves in lateral leads } Leads 1, V5,V6 5. Deep S waves in Right leads

Question 30

What are the ECG features in LBBB?

Answer 30

* -Further deepn ’S’ wave in V1 } **‘W’** * -Further ‘R’ wave in V6} **‘M’** * T wave inversion in anterolateral leads and is 2nd to abnormal repolarisation

Question 31

What is the pathophysiology of RBBB?

Answer 31

1. Left ventricle is activated as normal, impulse travels equally down the left and right bundles with 2. septum activated from left to right LV is activated as normal 3. so early part of QRS complex correlation to septal depolarisation is unchanged

Question 32

What are the ECG features in RBBB?

Answer 32

1. V1 : RSR pattern 'M' 2. V4/V5 : 'W': broad S wave in V6

Question 33

Bifascicular block RBBB + LAFB

Answer 33

R. Bundle branch block and left axis deviation

Question 34

Bifascicular block RBBB + LPFB

Answer 34

R. Bundle branch block and right axis deviation

Question 35

What is the defintion of QT interval?

Answer 35

Ventricular depolarisation and ventricular depolarisation Start of the QRS complex until the end of the T wave.

Question 36

Definition of ST segement

Answer 36

normally flat as no electrical activity, ventricles are already depolarised

Question 37

What is the function of the T wave?

Answer 37

- ventricular repolarisation, anything that affects depolarisation affects repolarisation - Check ; Orientation (upright/inverted), height * Normally inverted in - V2, II, III and AvF (inferior leads)

Question 38

Where are T waves normally inverted?

Answer 38

Normally inverted in - V2, II, III and AvF (inferior leads)

Question 39

What is the definition of Posterior STEMI?

Answer 39

Posterior STEMI - classically reciprocal changes in anterior leads >ST depression in V1, V2, V3 > Tall, broad R waves (30 secs) >Upright T waves