ECG Flashcards
What does an ECG do?
Looks at the electrical activity of the heart.
What is the pacemaker in relation to ECG?
The pacemaker dictates the rate at which the heart will cycle through its pumping action to circulate the blood. It creates an organised beating of all the cardiac cells in a specialised sequence. This sets the pace which the other cells will follow.
What is the SA node
The main area that acts as the hearts pacemaker, it controls the beat based on information it recieves from the nervous, circulatory and endocrine system.
Does the SA node always work?
No, however the AV node is used as backup. If the AV node does not work, the ventricle would then take over and beat around 40-45 beats per minute.
Where is atrial depolarisation/
In the SA NODE and atrium
What is a sinus rhythm?
Normal heart rhythm reflecting normal electrical acitivty.
How do you recognise a sinus rhythm?
The p waves are positive (upright) in lead 2, R-R and P-P intervals are regular.
What is sinus brachycardia?
Happens when the SA node fires at a slower pace for the patients age. Normally sinus brachycardia has a heart ratr of less than 60 bpm.
What is the first rule ?
All waves are negative in avr - predominantly QRS
What is the second rule?
The ST segment is isoelectric except in V1 and V2 where it may be elevated.
What is the third rule?
The PR interval should be 0.12 - 0.2 seconds (3-5 small squares)
What is the fourth rule?
The QRS segment should not exceed 0.12 seconds (3 small squares)
What is the fith rule?
The QRS and T waves should be the same direction in the standard limb Leeds
What is the sixth rule?
The R wave in the chest leads grows from at lease v1-v4
What is the seventh rule?
The QRS is mainly upright in leads 1, 2 and avf
