ECG

Question 1

What are the characteristic ECG changes in hyperkalaemia?

Answer 1

Tall tented T waves
Loss of P waves
QRS complex broadening
Sine-wave-shaped ECG
Cardiac arrest rhythms

Question 2

What are the characteristic ECG changes of hypokalaemia?

Answer 2

Flat, broad T waves
ST depression
Long QT interval
Ventricular dysrhythmias

Question 3

What distance should the P-R interval be?

Answer 3

Between 3 and 5 small squares (0.12-0.2secs)

Question 4

What is atrial fibrillation?

Answer 4

Used to describe erratic electrical activity in the atria

Question 5

What is seen on an ECG with atrial fibrillation?

Answer 5

No P waves

Irregularly occurring QRS complexes

Question 6

What is seen on an ECG with atrial flutter?

Answer 6

Flutter (F) waves (NOT P waves)

Irregular occurring QRS complex, and may have degree of AV block (e.g. 2:1)

Question 7

What do flutter waves appear like on an ECG?

Answer 7

Saw-toothed appearance

Question 8

What are the ECG features of first degree heart block?

Answer 8

P waves followed by QRS complex, but P-R interval is prolonged, but constant

Question 9

What three things must be present to diagnose sinus rhythm?

Answer 9

P wave preceding every QRS complex
P-R interval is normal
P-R interval is constant

Question 10

What are the ECG features of secondary degree heart block, Mobitz type 1?

Answer 10

P-R interval lengthens with successive heart beat, until a QRS complex is dropped.
Also called Wenckebach

Question 11

What are the ECG features of secondary degree heart block, Mobitz type 2?

Answer 11

Not every P wave associated with a QRS complex. Can have set rhythm, e.g. two-to-one.

Question 12

What are the ECG features of a third degree heart block?

Answer 12

Both P waves and QRS complexes present, but there is no association between them

Question 13

What are the best leads to look at for axis deviation?

Answer 13

Leads I and II

Question 14

What would the leads show in left axis deviation?

Answer 14

Lead I - upgoing

Lead II - downgoing

Question 15

What would the leads show in right axis deviation?

Answer 15

Lead I - downgoing

Lead II - upgoing

Question 16

What does P pulmonale describe and what conditions does it occur in?

Answer 16

Tall, peaked P waves

Seen in right atrial enlargement

Question 17

What does P mitrale describe and what conditions does it occur in?

Answer 17

Bifid P waves

Seen in patients with mitral stenosis

Question 18

What is the width of a normal QRS complex?

Answer 18

Three small squares (0.12secs)

Question 19

What ECG features are seen in RBBB?

Answer 19

Two upward deflections (two R waves) in V1 (the M shape)

A deep S wave in V6 (the W shape)

Question 20

What can LBBB on ECG be a sign of?

Answer 20

Myocardial infarction

Question 21

What are the ECG features of LBBB?

Answer 21

A stepped downward deflection in V1 (the W shape)

Two upward deflections (RSR pattern) in V6 (the M shape)

Question 22

What are the causes of ST segment elevation and what are the differences between them?

Answer 22

MI - convex upward ST elevation (in heart leads of damaged part)
Pericarditis - concave/saddle-shape upward ST elevation (in most/all ECG leads)

Question 23

What can horizontal ST depression signify?

Answer 23

Cardiac ischaemia, eg angina pectoris, NSTEMI

Question 24

What is the normal width of Q-T interval?

Answer 24

No more than two large squares

Question 25

What are shockable rhythms?

Answer 25

``` Ventricular fibrillation Ventricular tachycardia (pulseless) ```

Question 26

What is the QT interval measured from and to?

Answer 26

Beginning of QRS complex to end of T wave

Question 27

What can prolonged QT interval be a risk for?

Answer 27

Developing torsades de pointes (a life-threatening arrhythmia)

Question 28

What drugs can increase the QT interval?

Answer 28

``` Amiodarone Amitriptyline Chlorpromazine Haloperidol Levofloxacin Sumatriptan ```

Question 29

In a young healthy patient, what can breathing do to the heart rhythm?

Answer 29

Rate is faster on inspiration

Question 30

What is a pure delta wave a feature of?

Answer 30

Wolf-Parkinson-White syndrome

Question 31

What conditions can cause ventricular tachycardia?

Answer 31

MI Valvular heart disease Heart failure Electrolyte imbalances

Question 32

What are common causes of torsades de pointes?

Answer 32

Drugs that lengthen QT interval, eg amiodarone, erythromycin, haloperidol Myocardial ischaemia Electrolyte abnormalities, eg hypokalaemia

Question 33

What are the causes of pulseless electrical activity?

Answer 33

Hypoxia Hypovolaemia Hypo/hyperkalaemia Hypothermia Tension pneumothorax Tamponade (cardiac) Thrombus (PE) Toxins (drugs)