ECG Flashcards
What leads are ECG changes in if anterior infarction?
V1-V4
ECG changes in leads V1-V4 show what type of infarction and what coronary artery is affected?
Anterior
Left anterior descending
What leads are ECG changes in if inferior infarction?
II, III, aVF
ECG changes in leads II, III, aVF show what type of infarction and what coronary artery is affected?
Inferior
Right coronary artery
What leads are ECG changes in if lateral infarction?
I, aVL, V5-6
ECG changes in leads I, V5-V6 show what type of infarction and what coronary artery is affected?
Left circumflex artery
What does P wave represent?
Atrial depolarisation
What does the PR interval (start of P to start of Q) represent?
Time for electrical activity to move between atria and ventricles
What does the QRS complex represent?
Depolarisation of ventricles
What does the ST segment (end of S to start of T) represent?
time between depolarisation and repolarisation of the ventricles (ventricular contraction)
What does the T wave represent?
Ventricular repolarisation
What is the RR interval?
One R wave to the end of the next R wave. Time between 2 QRS complexes
What is the QT interval?
Starts of QRS to end of T. Time taken for ventricles to depolarise and then repolarise.
Small square
0.04s
Large square
0.2s
How many squares is 1 second?
5 large squares
How many squares is 1 minute?
300 large squares
How many electrodes (conductive pad that records electrical activity) and how many leads (graphical representation of heart’s activity calculated by analysing the electrodes) are used in ECG?
12 leads so 12 separate graphs on 1 ECG paper.
10 electrodes that attach to pt to generate the 12 leads.
How many electrodes?
10
Name the chest electrodes?
V1-V6
V1 location?
4th intercostal space at the right sternal edge
V2 location?
4th intercostal space at the left sternal edge
V3 location?
Midway between the V2 and V4 electrodes
V4 location?
5th intercostal space in the midclavicular line