ECG Flashcards
What colour is the lead placed on the left arm?
Yellow
What colour is the lead placed on the right arm?
Red
What colour is the lead placed on the left leg?
Green
What colour is the lead placed on the right leg?
Black
Where is the red lead placed?
Right arm
Where is the yellow lead placed?
Left arm
Where is the black lead placed?
Right leg
Where is the green lead placed?
Left leg
Where is the first chest lead (V1) placed?
Right sternal edge 3rd intercostal space
Where is the second chest lead (V2) placed?
Left sternal edge 3rd intercostal space
Where is the third chest lead (V3) placed?
Midway between V2 and V4
Where is the fourth chest lead (V4) placed?
Mid clavicular line 4th intercostal space
Where is the fifth chest lead (V5) placed?
Midway between V4 and V6
Where is the sixth chest lead (V6) placed?
Mid axillary line in the 4th intercostal space
What is the normal speed of the paper?
25 mm/sec
If the speed is set at 25 mm/sec, how much time does 1 big square represent?
0.2 seconds
If the speed is set at 25 mm/sec, how much time does 1 small square represent?
0.04 seconds
When describing an ECG what are the first two things you must check before even looking at the waves?
Name of patient Speed
What are the first things to assess when looking at any ECG?
Rate Rhythm
When assessing whether the heart is in normal sinus rhythm which lead do we tend to look at?
Lead II
Describe the rate of this ECG strip.
There are 2-4 large squares between each QRS, so a range of 75-150 is correct. Because the rate is so variable in this instance it is better to take an average by counting the QRS complexes in 30 big squares and multiplying ten to get an average rate. There are 9 QRSs in 30 squares. Therefore the rate is approx 90 bpm.
Describe the rhythm and regularity of this ECG strip.
The rhythm is hard to tell because the p waves are hard to distinguish. The QRS complexes are narrow so they are probably not ectopic ventricular beats.
The rhythm is also irregularly irregular.
Describe the PR interval of this ECG strip.
It is not possible to estimate the PR interval because of the lack of distinct p waves.
Describe the QRS complexes in this ECG strip.
The QRS duration is approximately 1 small square (0.04s). Normal is
What is the diagnosis based on this ECG strip?
Absent p waves and an irregularly irregular rhythm suggest a diagnosis of Atrial fibrillation.
Describe the rate of this ECG strip.
There are just over 2 large squares between QRS complexes. The rate must be a little lower than 150. There are 7 QRS complexes in 15 large squares and hence there would be 14 in 30 large squares. Therefore the rate is 140 bpm.
Describe the rhythm and regularity of this ECG strip.
There are no p-waves at all and the QRS complexes are all broad. It is definitely therefore not sinus rhythm and the beat are most likely originating in the ventricles themselves.
The rhythm is regular.
Describe the QRS complexes in this ECG strip.
The QRS complexes are broad and do not allow for any p- or t-waves.
What is the diagnosis based on this ECG strip?
The broad QRS complexes, fast ventricular rhythm and no visible p waves suggest a diagnosis of ventricular tachycardia.
Describe the rate of this ECG strip.
There are 5 large squares between QRS complexes so 300/5 = 60.
OR
There are 6 QRS complexes in 30 large squares so 6 x 10 = 60
Describe the rhythm and regularity of this ECG strip.
There are p waves before every QRS and the QRS complexes are all narrow so we can assume that the origin of the impulse is the atrium and most likely the SA node so it can be described as sinus rhythm.
The rhythm can also said to be regular.
Describe the PR interval in this ECG strip.
The PR interval is 7 small squares 0.04x7 = 0.28secs. This is outside of the normal range (0.12 - 0.2 seconds or 3-5 small squares).
What is the diagnosis based on this ECG strip?
Although the PR interval is prolonged, it is of constant length and there are no missing QRS complexes. Each of the QRS complexes follow the p wave. Therefore the diagnosis is 1st degree atrioventricular block.
Describe the rate, rhythm and regularity of the ECG strip.
There are 6 QRS complexes in 30 large squares so the rate is about 60 beats per minute.
Each QRS is preceeded by a p-wave and the QRS complexes are narrow therefore we can assume that the origin of the impulse is the atrium, most likely the SA node, therefore the rhythm is probably sinus.
The rhythm can also said to regularly irregular, where there is an ever increasing distance between QRS complexes followed by a missed beat before the cycle starts again.
What is the diagnosis based on this ECG strip? Explain your answer.
The PR interval is progressively prolonged, until an impulse fails to be conducted to the ventricles, and the cycle then repeats. This pattern suggests a diagnosis of second degree AV block, Mobitz type 1 (Wenckebach)
Describe the rate, rhythm and regularity of this ECG strip.
There are 5 QRS complexes in 30 large square so the rate is about 50 bpm.
Each QRS is preceeded by a p-wave and the QRS complexes are narrow therefore we can assume that the origin of the impulse is the atrium, most likely the SA node, therefore the rhythm is probably sinus.
The rhythm can also said to irregular, where there is no discernable pattern to the missed QRS complexes.
What is the diagnosis based on this ECG strip? Explain your answer.
The PR interval remains constant but there are missing QRS complexes. There is no discernable pattern or ratio therefore we simply call this a 2nd degree heart block, Mobitz type 2. There is a danger of this progressing to 3rd degree heart block.
