Electricity and the Heart

Question 1

aVR signal on ECG is positive or negative?

Answer 1

Negative so the peaks are upside down because main electrical flow is going away from aVR

Question 2

lead II is positive or negative?

Answer 2

Positive because main electrical impulses towards this electrode

Question 3

How to calculate the rate on an ECG?

Answer 3

Count the number of large squares between the big peaks (QRS complex) and divide into 300

Or count small squares and dividie into 1500 so 1500/ number

Question 4

What does P peak show on ECG?

Answer 4

Atrial depolarisation

Question 5

What does QRS complex show on ECG?

Answer 5

Ventricular depolarization

Question 6

What does T peak show on ECG?

Answer 6

Ventricular repolarization

Question 7

A full thickness damage- STEMi will show what on the ECG?

Answer 7

ST segment elevation, damaged cells repolarize early

Question 8

A subendocardial damage - NSTEMI will show what on an ECG?

Answer 8

ST segment depression - T wave inversion

Question 9

If inferior atomic region of heart is affected which coronary artery is most likely affected?

Answer 9

Right coronary

Question 10

If antero-septal atomic region of heart is affected which coronary artery is most likely affected?

Answer 10

Left anterior descending

Question 11

If antero-apical region of heart is affected which coronary artery is most likely affected?

Answer 11

Left anterior descending

Question 12

If antero-lateral atomic region of heart is affected which coronary artery is most likely affected?

Answer 12

Circumflex

Question 13

If posterior atomic region of heart is affected which coronary artery is most likely affected?

Answer 13

Right coronary

Question 14

An inferior myocardial infarction will affect which leads? and will show what?

Answer 14

ST elevation in leads II, III and aVF

Question 15

An anterior/septal myocardial infarction will affect which leads and show what?

Answer 15

ST elevation in leads V2, V3, V4

Question 16

What does a wide QRS complex show?

Answer 16

Problems with ventricles

Question 17

What does a narrow QRS complex show?

Answer 17

Problem with SA node

Question 18

Sign of hyperkalaemia in ECG

Answer 18

Tall T waves, QRS widening

Question 19

Hypertrophy signs in ECG

Answer 19

Large amplitude of QRS complex

Question 20

Signs of atrial fibrillation on ECG

Answer 20

No P waves

QRS normal, but irrregularly irregular

Question 21

What treatment for atrial fibrillation?

Answer 21

Antithrombotic- warfarin, aspirin

Rhythm- digoxin, beta blockers, Ca2+ antagonist etc.

Question 22

What does Digoxin do?

Answer 22

Slows conduction through AV node- reduces ventricular rate in AF

Question 23

Signs of ventricular fibrilation?

Answer 23

Continuous bizarre irregular trace

Question 24

What is a heart block?

Answer 24

Problem with conduction through AV node

Question 25

What are the different types of heart block?

Answer 25

First degree- all transmission but delayed- long PR interval, normal PQRS complex
2nd degree- partial transmission, some P waves without associated QRS complex, regular or variable
3rd degree- none- no link between P waves and QRS complex, broad QRS complex

Question 26

What is a bundle branch block?

Answer 26

A problem with conduction through the R or L bundle branch of Hiz

Question 27

What does ventricular ectopic look on ECG?

Answer 27

Wide, bizarre QRS complex

No P wave

Question 28

What does a pacing impulse (artefact) look like in an ECG

Answer 28

Instead of P wave have very brief impulse external impulse that stimulates ventricles
Wide QRS complex