Flashcards in ECG collated Deck (39)
How are dipoles created in the heart?
Different regions of the heart being polarised or depolarised
What do two dipoles generate?
An electrical field measurable with 2 electrodes
What is the imaginary line connecting 2 dipoles?
Measured potential difference is greatest when?
The lead axis is parallel to the direction of the dipole and 0 when perpendicular
Lead position on a 12 lead ECG?
1= RA- LA
2= RA- LL
Direction moving towards the the recording (+ve elctrode) gives what type of deflection?
Which electrode is the recording electrode?
Depolarization moving away from positive electrode causes?
Downwards stroke on ECG
What does the P wave signify?
How long does the P wave last?
What does Q wave signify?
Left to right depolarization of the interventricular septum
How long should the QRS complex be?
What does the R wave signify?
Depolarization of the main ventricular mass (moving towards recording electrode)
S wave signifies?
Depolarization of ventricles at base of heart (moving away from recording electrode)
What does T wave signify?
Where do you place lead 1 of an ECG?
4th IC space, RHS
Where do you place lead 2 of an ECG?
4th ICS, LHS
Where do you place lead 4 of an ECG?
5th ICS, mid-clavicular line
Where do you place lead 3 of an ECG?
Halfway between lead 2 and 4 on the rib/between them
Where do you place lead 5 on an ECG?
5th ICS, anterior axillary line
Where do you place lead 6 on an ECG?
5th ICS, mid axillary line
QRS complex signifies?
Ventricular depolarization (<1s)
PR interval signifies?
AV nodal delay
How long should PR interval be?
QT interval signifies?
Depolarization and repolarization of ventricles
What does a small box stand for on an ECG?
What does a large box stand for on an ECG?
How to find HR on an ECG?
300/no. of large squares between beats
How to find HR if irregular?
no. of QRS in 30 large squares x 10