QuestionSBA
QuestionChoice
T waves on an ECG represents the repolarisation of the ventricles.
Tall tented T waves are characteristic of hyperkalaemia and can be an early sign of an acute coronary syndrome.
10005940
e
Tall tented T waves
QuestionChoice
Atrial fibrillation results from multiple chaotic impulses being generated from the inside of the atrium. This results in fibrillation of the atria and impaired contraction.

A fibrillating baseline is seen and there is an absence of clear P waves.
10005936
a
Absence of P waves
QuestionChoice
This suggests that there is an irregular rhythm originating from the atria.

This can be seen in sinus arrhythmia. This is a physiological change seen in heart rate due to respiratory cycle. Seen in younger people.

Even though atrial fibrillation is an irregular rhythm from the atria, p waves tend to be absent from the chaotic impulses.
10005938
c
Variation in P - P wave interval
QuestionChoice
This is due to atrial flutter which is a macro-reentry circuit within the atria.

This results in a high rate of depolarisation of the atria > 250 bpm.

The AV node undergoes its normal function and blocks some of these impulses and only lets some through. Therefore, a ratio can be seen between sawtooth waves and QRS complexes - this can be regular and irregular.
10005937
b
Sawtooth waveform
QuestionChoice
This means that the P wave on an ECG is not followed by a QRS complex.

This is due to pathology in the AV node that relays the signal to ventricle. This is known as a heart block.
10005939
d
Non propagated P wave
Concept
Chapter
2693
3799
ECG
Topic
159
Cardiovascular physiology
13734
A 50 year old attends the GP with palpitations, dizziness and describes his heart 'racing' at times. These episodes are worsened by exercise and have stopped running as he is scared to faint.

The GP performs an ECG and the patient is subsequently diagnosed with atrial fibrillation (AF).

What is a feature of atrial fibrillation (AF) on an ECG?
a