Common Arrhythmias (+ ECG interpretations)

Question 1

What will an ECG of someone with sinus rhythm (normal) look like?

Answer 1

All p waves are followed by a QRS wave

Rate is regular and normal

Question 2

What will an ECG of someone with sinus bradycardia look like?

Answer 2

All p waves are followed by QRS complexes

Rate is regular but slow

Question 3

What will an ECG of someone with sinus tachycardia look like?

Answer 3

All p waves followed by QRS complexes

Rate is regular but fast

Question 4

What will an ECG of someone with sinus arrhythmia look like?

Answer 4

All p waves followed by a QRS complex, rate is irregular and normal ish, R-R interval varies with breathing cycle

Vagus nerve usual slows heart beat but in sinus arrhythmia vagus nerve stops slowing it during inspiration

Question 5

What will an ECG of someone with atrial fibrillation look like?

Answer 5

There is an oscillating baseline (atria contracting asynchronously) , rhythm is irregular and rate may be slow
Turbulent flow pattern increases clot risk

Question 6

What will an ECG of someone with atrial flutter look like?

Answer 6

Regular saw tooth pattern in the baseline ( II, III, aVF), atrial to ventricular beats at a ratio of 2:1, 3:1 or higher
Saw tooth not always visible on all leads

Question 7

What does atrial fibrillation increase risk of and why?

Answer 7

Blood clots due to turbulent flow

Question 8

What will an ECG of someone with first degree heart block look like?

Answer 8

Prolonged PR interval due to slow AV conduction
There is regular rhythm and normal ratio of p waves to qrs complexes
Progressive disease of aging

Question 9

What will an ECG of someone with second degree heart block (mobitz I) look like?

Answer 9

Gradually prolonged PR interval until a beat is skipped, so most p waves are followed by a qrs complex but some arent
Regularly irregular, caused by diseased AV node
AKA. Wenckebach

Question 10

What will an ECG of someone with second degree heart block (mobitz II) look like?

Answer 10

P waves are regular but only some are followed by a qrs complex
No PR prolongation
Regularly irregular (success to failure)
Can rapidly deteriorate to 3rd degree heart block

Question 11

What will an ECG of someone with third degree heart block look like?

Answer 11

P waves and QRS complexes are regular but there is no connection between them
P waves can be hidden in bigger vectors
Needs a pacemaker

Question 12

What will an ECG of someone with ventricular tachycardia look like?

Answer 12

P waves are hidden
Rate is regular and fast
At risk of deteriorating into fibrillation (cardiac arrest)
Shockable rhythm

Question 13

What will an ECG of someone with V fib look like?

Answer 13

Heart rate is irregular and very very fast (250bpm +)
Heart unable to generate an output
Shockable rhythm

Question 14

What will an ECG of someone with ST elevation look like?

Answer 14

ST segment is elevated over 2mm above the isoelectric line, P waves are visible and always followed by a QRS complex
Rhythm is regular and rate is normal
Caused by infarction

Question 15

What will an ECG of someone with ST depression look like?

Answer 15

ST segment is depressed over 2mm below the isoelectric line, P waves are visible and always followed by a QRS complex
Rhythm is reg and normal
Caused by myocardial ischaemia

Question 16

Which arrhythmias are shockable?

Answer 16

Ventricular tachycardia or ventricular fibrillation