Abnormal rhythm ECG

Question 1

What is an extrasystole/ectopic beat?

Answer 1

Any part of the heart that depolarises earlier than it should

Question 2

What is an atrial extrasystole?

Answer 2

• Abnormal P wave, as P wave represents atrial depolarisation
• Normal QRS complex
• Abnormal P wave is followed by a pause (delay)

Question 3

What is a junctional extrasystole?

Answer 3

• P wave is absent, or P wave is immediately before, or after the QRS
• QRS complex is normal

Question 4

What is a ventricular extrasystole?

Answer 4

• Absent P wave
• Wide QRS complex (as it originates in the ventricles) that is > 3 small squares
• Inverted T wave
• Followed by a pause

Question 5

When are ventricular extrasystoles clinically significant?

Answer 5

• R on T phenomenon

Can cause Ventricular tachycardia

Question 6

What are the bradycardic rhythms?

Answer 6

Atrial escape rhythms
- SAN fails to depolarise, so atrial muscles take over as the sight of firing

Nodal/Junctional escape rhythms
- SAN fails to depolarise, AVN takes over

Ventricular escape rhythms
- Either SAN fails to depolarise, or due to complete AV block

Question 7

What does an atrial escape rhythm look like on an ECG?

Answer 7

• Abnormal P-wave
• Normal QRS complex
• Preceded by a pause (due to failure of SAN to depolarise & the time it takes for the atrial muscle to become the firing focus)
• HR: 60-80 bpm

Question 8

What does an nodal/junctional escape rhythm look like on an ECG?

Answer 8

• Absent P-wave (because firing focus is in AV node)
• Normal QRS complex
• Preceded by a pause
• HR: usually 40-60 bpm

Question 9

What does an ventricular escape rhythm look like on an ECG?

Answer 9

• Absent or normal P-wave
• Wide QRS complex (as ventricles are site of firing focus)
• Abnormal T-wave
• Preceded by a pause
• HR: usually 20-40 bpm

Question 10

What are the regular tachycardias?

Answer 10

SVT

• Sinus tachycardia
• Atrial tachycardia
• Atrial flutter
• Junctional Tachycardia
• AVNRT
• AVRT

VT

Question 11

What are the irregular tachycardias?

Answer 11

SVT

• A-fib
• MAT

V-fib

Question 12

How does atrial tachycardia look on an ECG?

Answer 12

• No P-waves
• Narrow QRS
• Regular rhythm

Question 13

How does atrial flutter look on an ECG?

Answer 13

• Saw-tooth P-waves
• Narrow QRS
• Regular rhythm

Question 14

How does ventriuclar tachycardia look on an ECG?

Answer 14

• No P-waves
• Wide QRS
• Regular rhythm

Question 15

How does atrial fibrillation look on an ECG?

Answer 15

• No P-waves

- Irregularly irregular rhythm

Question 16

How does ventricular fibrillation look on an ECG?

Answer 16

• No identifiable P waves, QRS complexes, or T waves