ECG analysis Flashcards
What is the 3 step procedure to analysis ECG’s?
Rate - Large squares or small squares method
Rhythm - P-R interval (P wave to beginning or qrs complex). QRS duration. ST segment (normal, elevated e.t.c).
For rate and rhythm use rhythm lead.
Axis - LAD or RAD.
What is the ecg axis?
Average direction of electrical movement through heart.
What causes axis deviation?
Changes in position of electrical conduction - e.g ventricular hypertrophy results in more muscle and so more electrical conduction.
Change in position of heart.
What causes right axis deviation?
Right ventricular hypertrophy or left ventricle damage. Tall, thin people due to a lower diaphragm and so heart is positioned more towards the right.
Key characteristic of atrial fibrilation?
Loss of p wave.
Key characteristic of atrial flutter?
Sawtooth pattern.
What do heart blocks involve?
AV node either delaying conduction or blocking conduction.
What is a 1st degree heart block involve?
Longer PR interval as there is a delay in conduction.
What does a 2nd degree heart block involve?
Absence of QRS complex as there is a loss of conduction.
What leads should be focused on?
I,II,III,AVR,AVF,AVL.
How long should the qrs complex be?
120 - 200 ms.
Why is lead II used to detect cardiac arrythmias?
Lies close to the cardiac axis. Lead goes from right arm to left leg. Heart is positioned towards left too.
What do v leads look at?
Axial plane, rotation of heart.
