Rhythm disorders

Question 1

Checks to perform on an ECG

Answer 1

1. Correct recording? (px name/age/EMIS)
2. Review the signal quality and leads
3. Verify the voltage and paper speed
4. Review the patient background

Question 2

What is the step by step process of interpreting an ECG?

Answer 2

Rate and Rhythm
P-wave and P-R interval
QRS duration
QRS axis (cardiac axis)
ST segment
QT interval/T wave

Question 3

What are the features of a sinus rhythm ECG?

Answer 3

Each P wave is followed by a QRS complex (1:1) // Regular rate and normal bpm

Question 4

What are the features of a sinus bradycardia ECG?

Answer 4

Each P wave is followed by a QRS complex (1:1)
Regular rate but SLOW bpm (<65)

Question 5

What are the features of a sinus tachycardia ECG?

Answer 5

Each P wave is followed by a QRS complex (1:1)
Regular rate but FAST bpm (>100)

Question 6

What are the features of a sinus arrhythmia ECG?

Answer 6

Each P wave is followed by a QRS complex (1:1)
Irregular rate (variable R-R intervals)
Normal range of bpm (65-100)

Question 7

What does sinus mean?

Answer 7

Rhythm generated by the SAN

Question 8

What can cause sinus bradycardia

Answer 8

Medication
Normal - red. HR for athletes due to muscular heart
Vagal stimulation

Question 9

What can cause sinus tachycardia

Answer 9

physiological response to stimulus

Question 10

When can rate be faster and slower in sinus arrhythmia?

Answer 10

Slower - long expiration
Faster - long inspiration

Question 11

How to calculate Heart rate

Answer 11

300/no. large squares

Question 12

What is happening in atrial fibrillation?

Answer 12

Abnormal irregular contraction of atria

Question 13

What are the features of an atrial fibrillation ECG?

Answer 13

Oscillating baseline (atria contracts asynchronously), Irregular Rhythm,
Slow Rate

Question 14

What is a complication of atrial fibrillation?

Answer 14

Clotting - due to turbulent flow

Question 15

What is happening in atrial flutter?

Answer 15

Abnormally fast REGULAR contraction of atria

Question 16

What are the features of an atrial flutter ECG?

Answer 16

Saw-tooth pattern in baseline (not present in everyone)
Multiple P waves followed by QRS complex (2:1 or 3:1)

Question 17

What is happening in first degree heart block?

Answer 17

Delay in Atrioventricular Node in conducting QRS complex, typically with aging

Question 18

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

Answer 18

Prolonged PR segment/interval
Regular rhythm

Question 19

What causes first degree heart block

Answer 19

Ageing

Question 20

What are the two types of second degree heart block?

Answer 20

Mobitz Type I and Mobitz Type II

Question 21

What is happening in second degree heart block?

Answer 21

Delay in Atrioventricular Node in conducting QRS complex, sometimes current does not reach the ventricles

Question 22

What are the features of a Mobitz Type I Second Degree Heart Block ECG?

Answer 22

Gradual prolongation of PR segment/interval until there is a missing QRS.
Regularly irregular - (beat, beat, no beat) looped.

Question 23

What is the cause of Mobitz 1 2º HB

Answer 23

diseased AVN

Question 24

What are the features of a Mobitz Type II Second Degree Heart Block ECG?

Answer 24

No PR prolongation,
Regular P waves
Some missing QRS
Regular irregular (can follow 2:1 pattern or be completely random)

Question 25

What can mobitz II 2º HB deteriorate into

Answer 25

3º HB

Question 26

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

Answer 26

P-P intervals are regular R-R intervals are regular But P and R intervals are completely irregular - non-sinus rhythm

Question 27

What is happening in third degree heart block?

Answer 27

Complete block of AVN However ventricular contraction still occurs (self stimulating), disjointed w/ atrial contrac

Question 28

What is happening in ventricular tachycardia?

Answer 28

Ventricles are contracting too fast, disjointed atrial contraction, but regularly

Question 29

What are the features of a ventricular tachycardia ECG?

Answer 29

Hidden P waves, Regular and Fast Rate (100-200)

Question 30

V.Tach risks

Answer 30

Cardiac arrest with deterioration in fibrillation .: use defibrillator (shockable rhythm)

Question 31

What is happening in ventricular fibrillation?

Answer 31

Cardiac Arrest - irregular extremely fast ventricular contractions (uncoordinated e- activity)

Question 32

What are the features of a ventricular fibrillation ECG?

Answer 32

Irregular heart rate over 250bpm

Question 33

How can you treat ventricular arrythmias?

Answer 33

Defibrillator - they are shockable rhythms

Question 34

What is an example of a non-shockable rhythm?

Answer 34

Flat-lining - asystole (adrenaline injections)

Question 35

What causes movement of the ST segment

Answer 35

Perfusion defect

Question 36

What is happening in ST-Elevation?

Answer 36

Perfusion defect caused by infarction (tissue death due to hypoperfusion)

Question 37

What are the features of an ST-Elevation ECG?

Answer 37

1:1 P waves and QRS complexes Regular rate and normal BPM ST segment is elevated by more than 2mm (2 tiny boxes) above isoelectric line

Question 38

What is happening in ST-Depression?

Answer 38

Perfusion defec due to myocardial ischaemia (coronary insufficiency/hypoxia)

Question 39

What are the features of an ST-Depression ECG?

Answer 39

1:1 P waves and QRS complexes Regular rate and normal BPM ST segment is depressed more than 2mm (2 tiny boxes) below isoelectric line

Question 40

Infarction vs Ischaemia

Answer 40

Infarction: Blood flow completely cut off -> necrosis Ischaemia: Red. blood flow -> hypoxia