Arrythmias

Question 1

What are features of normal sinus rhythm on the rhythm strip of an ECG

Answer 1

Intrinsic rate of 60 to 100 beats/minute
Regular, with minimal variation between R-R intervals
P wave is present, upright, and precedes each QRS
complex
PRI between 0.12 and 0.20s
QRS <0.12s

Question 2

What are features of sinus bradycardia on the rhythm strip of an ECG - include how to identify if treatment is necessary

Answer 2

Rate of less than 60 beats/minute
Rhythm is regular
PRI and QRS normal range
Treatment focuses on the patient’s tolerance to the bradycardia

Question 3

What are features of sinus tachycardia on the rhythm strip of an ECG - include info on treatment

Answer 3

Rate of more than 100beats/minute
Rhythm is regular
PRI and QRS normal range
Treatment is related to the underlying cause

Question 4

What are features of sinus arrhythmia on the rhythm strip of an ECG

Answer 4

Slight variation of a sinus rhythm
Shorter / longer RR intervals depending on inspiration / expiration
Increases stroke volume and blood pressure
Bainbridge reflex - initiated by changes within the breathing cycle
Normal finding in children and young adults

Question 5

What are features of sinus arrest on the rhythm strip of an ECG

Answer 5

An entire PQRST(s) is/are missing
The rhythm is regular apart from the dropped beat
SA node fails to initiate an impulse
SA node resumes normal functioning
Occasional episodes are not significant
Treatment based on the overall HR and tolerance

Question 6

What are features of a PAC on the rhythm strip of an ECG

Answer 6

Premature atrial complex:
The underlying rhythm is regular
Premature and abnormally
shaped P wave on the PAC
Also known as atrial ectopic
Occurs earlier in time than the
next expected sinus complex
Treatment is usually not
indicated

Question 7

What are features of SVT on the rhythm strip of an ECG - include treatment

Answer 7

Supraventricular tachycardia:
Rhythm is regular
The P wave is lost in the preceding T wave because of the fast rate
“Pacemaker” site above the ventricles
Generally above 150bpm
Treatment - medication or electrical cardioversion or pacing or Valsalva maneuver

Question 8

What are features of atrial flutter on the rhythm strip of an ECG - include treatment

Answer 8

Ventricular rate is less than the atrial rate
Classic (saw-tooth) flutter waves
Can be regular or irregular
Atria contract at a rate too rapid for the ventricles to match
Known as flutter or F waves
Can have variable ratio of F wave: QRS complex (1:1, 2:1, 3:1 etc)
Treatment - medication or cardioversion

Question 9

What are features of atrial fibrillation on the rhythm strip of an ECG

Answer 9

Rhythm is irregularly irregular
P waves replaced by erratic fibrillatory waves
Rhythm in which the atria fibrillate or quiver without organised contraction
Cells depolarise independently

Question 10

What are features of junctional rhythms on the rhythm strip of an ECG

Answer 10

Absent or inverted P waves
Rate of 40 - 60 bpm
Caused by SA node and atria failing to initiate impulse - AV node can take over
If there is an inverted P wave before the QRS complex the atria have depolarised first
If there is an inverted P wave after the QRS complex the ventricles have depolarised first
If the P wave is absent, it is hidden by the QRS complex as the atria and ventricles have depolarised simultaneously

Question 11

What are features of accelerated junctional rhythms on the rhythm strip of an ECG

Answer 11

All the same features as a junctional rhythm (inverted / absent P waves) but the rate exceeds 60 bpm but is still less than 100bpm