ECG Flashcards
what is a ecg
used to record the electrical activity of the heart from different angles.
how are ecgs recorded?
by placing electrodes on a patient
what is a 12 lead ecg
generated by 10 electrodes attached to the patient
what do p waves represent?
represents atrial depolarization ( a change within the cell from the elctrical charge)
what does the PR interval represent?
the time it takes for a electrical charge to get from the atria to the ventricles
what does the ST segment represent?
the time between depolarizing ation and repolarization of the ventricles
what does the qt interval mean?
the time taken from the QRS wave to the T wave for the ventricles to depolarize and repolarize
what is a patients normal heart rate?
60-100bpm
what is a techycardia (fast) average heart rate
100>bpm
what is a bradycardia average heart rate?
<60bpm
how would you calculate a heart rate of someone who is regular?
count the number of large squares within 1 r-r interval and divide by 300
how would you calculate somebody’s heart rate who is irregular?
count the number of QRS complexes on a rhythm strip, multiply by 6= how many there is in 1 minute.
what does the cardiac axis represent?
overall direction of electrical activity.
in a healthy individual, where should the lines of a cardiac axis place?
between -30 degrees and 90
when the electrical activity is travelling towards a ECG lead there is there a positive or negative deflection?
positive
when the electrical activity is travelling towards a ECG lead there is there a positive or negative deflection?
negative
how long should the P wave be?
120-200ms (3-5 small squares)
how many seconds does 5 large squares equal?
1 second
how many sqaures equal to 1 minute
300 large squares
were do the V1 red electrode go
4th intercostle space on the right edge
were do the v2 yellow electrode go
4th intercostal space on the left
were does the v3 green electrode go
midway between the v2 and v4 electrodes
were does the v4 blue electrode go
5th intercostal space in the midclavicular
were does the v5 orange electrode go
left anterior, same horizontal level as v4
were does the v6 purple electrode go
left mid axillary same horizontal as v4 and v5
were does the 3 electrodes go on a 3 lead ECG
RA and LA under the collerbone
LL- lower edge of the left ribcage
