1b// Electrocardiogram & rhythm disorders Flashcards
why is ECG used?
cheap
easy to undertake
reproducible
quick turnaround on results/reporting
what is ECG used to view/diagnose?
conduction abnormalities
structural abnormalities
perfusion abnormalities
what are ECG electrodes?
sticky pads placed on body
what are ECG cables/wires?
cables with coloured ends attached to machine and body
what are ECG leads?
heart perspectives based on where the electrodes are placed
what do the characteristics of deflections on the leads mean?
width of deflection - duration of event
steepness of line - velocity of action potential
downward deflection - towards -ve electrode
upward deflection - towards +ve electrode
what are the normal deflections on an ECG?
P wave - small upwards
QRS complex - tiny down large up tiny down
T wave - small but long upwards
what does the P wave of an ECG tell you?
conduction of sinoatrial node and atrial depolarisation
what does the pause between P and Q on an ECG represent?
atrioventricular node depolarisation
what is represented by the isoelectric line just before Q on an ECG?
rapid conduction down bundle of His
what is represented by the Q complex on an ECG?
bundle branches depolarisation/septal depolarisation
what is represented by the R wave of an ECG?
apex of heart purkinje fibre depolarisation
what is represented by the S wave of an ECG?
purkinje fibres depolarising up the side of the myocardium
what is represented by the isoelectric line between S and T waves on an ECG?
fully depolarised ventricles
what represents the T wave on an ECG?
ventricular repolarisation
what is the electrode placement for an ECG?
V1 - right sternal border of 4 IC space V2 - left sternal border of 4 IC space V3 - midway between V2/4 V4 - mid clavicular line of 5 IC space V5 - midway between V4/6 V6 - mid axillary line of 5 IC space electrodes on both limbs on both sides
what lead goes between right and left arm?
rule of Ls - lead I
what lead goes between right arm and left leg?
rule of Ls - lead II
what lead goes between left arm and left leg?
rule of Ls - lead III
how do you read ECG findings?
rate&rhythm P wave/P-R interval QRS duration QRS axis ST segment QT interval T wave
what is sinus rhythm on an ECG?
each P wave followed by QRS
normal and regular rate
otherwise unremarkable