Electrocardiography

Question 1

Positive / Negative

RV Apex pacing gives rise to what ECG deflection in the inferior leads?

Answer 1

Negative.

Question 2

Positive / Negative

RVOT pacing gives rise to what ECG deflection in the inferior leads?

Answer 2

Positive.

Question 3

60,000 / Interval (msec) =

Answer 3

Rate in BPM.

Question 4

60,000 / Rate (in BPM) =

Answer 4

Interval in msec.

Question 5

Leads V1 - V6 are also known as the _____ leads.

Answer 5

Precordial.

Question 6

RA, LA, RL, LL are also known as the ____ leads.

Answer 6

Limb.

Question 7

1 Small ECG Square @ 25mm/s sweep = ___ms.

Answer 7

40ms.

Question 8

1 Large ECG Square @ 25mm/s sweep = ___ms.

Answer 8

200ms.

Question 9

True / False

1 Large ECG Square = 5 Small ECG Squares.

Answer 9

True.

40ms x 5 = 200ms.

Question 10

True / False

Standard ECG Sweep Speed is 50mm/sec.

Answer 10

False.

Standard is considered 25mm/sec.

Question 11

True / False

At standard calibration 10mm on the vertical axis = 1mV.

Answer 11

True.

Question 12

True / False

Normal ECG axis is considered between -30 to +90°.

Answer 12

True.

Question 13

Lead I Negative & Lead AVF Negative = _____ Axis.

Answer 13

Right Superior Axis.

Question 14

Lead I Negative & Lead AVF Positive = _____ Axis.

Answer 14

Right Axis.

Question 15

Lead I Positive & Lead AVF Positive = _____ Axis.

Answer 15

Normal Axis.

Question 16

Lead I Positive & Lead AVF Negative = _____ Axis.

Answer 16

Left Superior Axis.

Question 17

RV apex/septal pacing propagates via myocardial cells, which takes longer than the His Purkinje system. Thus what type of BBB does the surface ECG resemble at these pacing sites?

Answer 17

Left Bundle Branch Block.

Question 18

Epicardial LV pacing propagates via myocardial cells, which takes longer than the His Purkinje system. Thus what type of BBB does the surface ECG resemble at this pacing site?

Answer 18

Right Bundle Branch Block.

Question 19

Does Unipolar or Bipolar pacing elicit a large stimulus spike on the surface ECG?

Answer 19

Unipolar pacing.

Question 20

Why does a Unipolar pacing signal elicit a large stimulus spike on the ECG?

Answer 20

Generator Can is active - thus current travels through the body to reach the lead tip.

This large current field is detected via the surface ECG. With Bipolar systems the generator is not active. All current is contained within the leads, thus stimulus spike is small or non-existent.

Question 21

Positive / Negative

RV Apical pacing will show what deflection in lead I?

Answer 21

Positive.

Question 22

Positive / Negative

RVOT pacing will show what deflection in Lead I?

Answer 22

Positive.

Question 23

Positive / Negative

RV Apical pacing will show what deflection in lead aVR?

Answer 23

Positive.

Question 24

Positive / Negative

RVOT pacing will show what deflection in lead aVR?

Answer 24

Negative.

Question 25

A notch 0.04ms on the ascending limb of the S wave is called _____ sign?

Answer 25

Cabreras sign. ## Footnote *Often indicates old Myocardial Infarction.*

Question 26

In the presence of Cabreras sign, what two things can be ruled out as the cause of the notch?

Answer 26

1. Retrograde P-waves 2. Ventricular Fusion Beats

Question 27

What does the memory effect refer to with regard to cardiac pacing?

Answer 27

The continued inversion of T-waves post pacing. ## Footnote *The duration of this abnormal depolarisation/repolarisation is dependent on the duration of pacing.*

Question 28

When placing an RV lead, a dominant R-wave is seen in leads V1, V2 and V3. What should this give suspicion of?

Answer 28

LV pacing. ## Footnote *LV could be reached via CS, PFO or subclavian artery.*

Question 29

# True / False RVOT pacing generates an LBBB pattern with inferior axis.

Answer 29

True.

Question 30

Does septal lead placement generate a negative or positive deflection in Lead I?

Answer 30

Negative (Could also be isoelectric).

Question 31

Notching is observed in the inferior leads, where could the RV lead have been placed?

Answer 31

Free Wall.

Question 32

What is the rhythm?

Answer 32

Complete heart block.

Question 33

What is the rhythm?

Answer 33

Sinus Rhythm.

Question 34

What is the rhythm?

Answer 34

Complete heart block.

Question 35

What is the rhythm?

Answer 35

Second Degree AVB (Mobitz I).

Question 36

What is the rhythm?

Answer 36

Second degree AVB (Mobitz II).

Question 37

What is the rhythm?

Answer 37

First degree AVB.

Question 38

What is the rhythm?

Answer 38

Junctional Rhythm.

Question 39

# RBBB / LBBB Which type of block is seen here?

Answer 39

RBBB. ## Footnote *Reasonably narrow QRS complex with W pattern.*

Question 40

# RBBB / LBBB Which type of block is seen here?

Answer 40

LBBB. ## Footnote *Grossly broad QRS complex.*

Question 41

What is the rhythm?

Answer 41

Atrial Flutter.

Question 42

What is the rhythm shown here?

Answer 42

Ventricular Bigeminy.

Question 43

What is the rhythm shown here?

Answer 43

Ventricular Trigeminy.

Question 44

What is the rhythm shown here?

Answer 44

Ventricular Tachycardia.

Question 45

What is the rhythm shown here?

Answer 45

Ventricular Fibrillation.

Question 46

With regard to pacing, what is an issue that needs addressing?

Answer 46

Atrial non-capture. Check threshold and adjust output.

Question 47

What is the appropriate course of action? 'Asymptomatic 20yr old male under investigation for sleep apnoea records the following ECG during sleep study'. 1. Implant VVI pacemaker 2. Implant DDD pacemaker 3. Observation 4. Administer atropine

Answer 47

3 - Observation. ## Footnote *ECG shows high grade AVB with junctional escape rhythm. Not uncommon in young people during sleep hours. Patient is asymptomatic thus no indication for pacing.*

Question 48

Which of the following is most indicitave of transseptal perforation with LV capture? 1. LBBB 2. RBBB 3. Grossly broad QRS complex 4. Posterior Hemiblock 5. Inferior Axis

Answer 48

2 - RBBB. ## Footnote *Pacing from the left will give RBBB and vice versa for right hand side pacing.*

Question 49

# Yes/No Dr. requests revision due to LOC. Are they correct?

Answer 49

No - ECG shows no LOC (QRS following every pacing spike). Each paced beat is followed by intrinsic ectopic. PR interval of ~400msec is consistent with search AV hysteresis algorythm.