ECGs

Question 1

Sinus rhythm

Answer 1

The normal rhythm starting in the sinoatrial node normally at a rate of 60-100 BPM.
This can be seen by positive P wave in lead II & negative P wave in aVR

Question 2

Sinus tachycardia

Answer 2

Sinus rhythm with over 100 beats per min
Can be detected by 300/ number of large squares between R waves if rhyhtm is regular

Question 3

Sinus bradycardia

Answer 3

Sinus rhythm with under 60 beats per min
Can be detected by 300/ number of large squares between R waves if rhyhtm is regular

Question 4

Atrial Fibrillation

Answer 4

Tachycardic arrythmia when signals through the heart are started and scattered rather than just a single clear signal.
Can be seen as irregularly irregular rythm with no P waves and an unstable baseline (especially in V1)

Question 5

Atrial flutter

Answer 5

Tachycardic arrythmia where signal in the atrium loops in a circuit rather than following the usual pathway.
This can be seen as a sawtooth pattern of P waves not associated with QRS complex best seen in leads II, III & aVF

Question 6

First degree heart block

Answer 6

Delayed conduction at the AV node
This can be seen by a prolonged PR interval over 1 large square

Question 7

Second degree heart block mobitz I (Wenckeback)

Answer 7

Progressive delay of conduction from the SA node to the AV node until the signal is not conducted
This can be seen by a lengthening of the PR interval until there is a missed QRS complex

Question 8

Second degree heart block mobitz II

Answer 8

When P wave signal does not always transmit beyond the AV node.
This can be seen by missed QRS complex intermittently ithout lengthening of the PR interval as a regularly irregular rate

Question 9

Complete heart block

Answer 9

The lack of communication between the atria and the ventricles.
This can be seen by lack of association between P waves and QRS complex (P waves can be hidden by QRS)

Question 10

LBBB

Answer 10

When the left bundle branch does not conduct signal resulting in delyed contraction of the left ventricle.
This can be seen as a broad QRS complex with W shaped QRS in V1 and M shaped QRS in V6.

Question 11

RBBB

Answer 11

When the right bundle branch does not conduct signal resulting in delyed contraction of the right ventricle.
This can be seen as a broad QRS complex with M shaped QRS in V1 and W shaped QRS in V6.

Question 12

Anteroseptal MI

Answer 12

Occlusion of the artery supplying to the anterior or septal wall
This can be seen as ST elevation on at least 2 contiguous leads V1-V4

Question 13

Lateral MI

Answer 13

Occlusion of the artery supplying to the lateral wall
This can be seen as ST elevation on at least 2 contiguous leads I, aVL, V5-V6

Question 14

Inferior MI

Answer 14

Occlusion of the artery supplying to the inferior wall
This can be seen as ST elevation on at least 2 contiguous leads II - III, aVF

Question 15

Ischaemia

Answer 15

The stage before infarction in which there is reduced blood flow to the tissue.
This can be seen as pathological Q waves, ST depression or inverted T waves (T wave inversion is normal in leads III, aVR & V1)

Question 16

Checking heart rate

Answer 16

If regular, divide 300 by number of large squares between R waves.
If irregular, multiply by 10 the number of R waves in a 6 second period (30 large squares)

Question 17

6 step ECG checking

Answer 17

Check for electrical activity and signs of fibrillation/ flutter in baseline
Check ventricular rate and if it is regular
Check if there is ST elevation/ pathological Q wave
Check for wide QRS
Check for P waves and if they are followed by QRS or prolonged
Check for axis deviation
Check for T wave inversion/ hyperacute/ long or short QT interval

Question 18

Right axis deviation

Answer 18

When the heart has an angle of 90 to 180 degree instead of the normal -30 to 90 degree.
This can be seen by negative lead I and positive aVF

Question 19

Left axis deviation

Answer 19

When the heart has an angle of -30 to -90 degree instead of the normal -30 to 90 degree.
This can be seen by positive lead I and negative aVF

Question 20

Posterior MI

Answer 20

Occlusion of the artery supplying to the posterior wall
This can be seen as ST depression on at least 2 contiguous leads V1-V3 with ST elevation on V7-V9

Question 21

Right ventricular inferior MI

Answer 21

Occlusion of the artery supplying to the inferior wall affecting the right ventricle
This can be seen as ST elevation on at least 2 contiguous leads II - III, aVF and V4R