Flashcards in ECG Theory Deck (62)
Where on the chest should V1 be placed?
Right sternal edge, 4th intercostal space
Where on the chest should V2 be placed?
Left sternal edge, 4th intercostal space
Where on the chest should V3 be placed?
Midway between V2 and V4
Where on the chest should V4 be placed?
Mid-clavicular line, 5th intercostal space
Where on the chest should V5 be placed?
Anterior axillary line, same level as V4
Where on the chest should V6 be placed?
Mid axillary line, same level as V4
Which colour of limb lead corresponds to each of the bony prominences?
Right arm red, left arm yellow, left leg green, right leg black
One small box on an ECG is equal to what amount of time? One large box is equal to what amount of time?
0.04 secs / 0.2 secs
How is the rate calculated from an ECG of a person with a regular pulse?
300 divided by the number of large boxes between two R waves
How is the rate calculated from an ECG of a person with an irregular pulse?
The number of QRS complexes in 30 large squares multiplied by 10
What 5 questions should you ask yourself to ascertain the rhythm of an ECG?
1. Is there electrical activity present? 2. Is the rhythm regular or irregular? 3. Are P waves present? 4. What is the relationship between the P waves and QRS complexes? 5. What is the QRS duration?
How can you tell if the axis of an ECG is normal?
The QRS complex in leads I and aVF will both be positive
How can you tell if the axis of an ECG is deviated to the left?
The QRS in lead I will be positive but in aVF will be negative
How can you tell if the axis of an ECG is deviated to the right?
The QRS in lead I will be negative but in aVF will be positive
What does left axis deviation suggest?
LVH or damage to the right ventricle
What does right axis deviation suggest?
RVH or damage to the left ventricle
What is the PR interval?
The time from the onset of the P wave to the onset of the QRS complex
What does the PR interval represent in the cardiac cycle?
The beginning of atrial depolarisation to the beginning of ventricular depolarisation
What is the normal value of the PR interval?
120-200ms (3-5 small squares)
The duration of the QRS complex is considered normal when?
It is < 120ms (3 small squares)
What is the QT interval?
The beginning of the QRS until the end of the T wave
What does the P wave represent in the cardiac cycle?
What does the QRS complex represent in the cardiac cycle?
What does the T wave represent in the cardiac cycle?
The T wave should not be more than how high?
Half the height of the QRS
Supraventricular rhythms originate where? Describe their QRS complexes?
From the AV node or above / narrow QRS complexes
What are the two main features of sinus rhythm?
A P wave for every QRS and QRS for every P wave / PR interval < 200ms (one large box)
What is a sinus arrhythmia?
When an ECG meets all the criteria of sinus rhythm, but the rhythm itself is irregular
What are the two main features of atrial fibrillation on ECG?
No P waves / Irregularly irregular QRS