12 lead ECG Flashcards
How is an ECG wave formed
-if electrical vector directed towards the electrode, it causes a positive deflection, causing an upwards peak on an ECG
-if electrical vector directed away from electrode, causes a negative deflection causing a downward peak on an ECG
Acquiring ECG
-ECG wires, electrodes/ sticker/ dots
-need stickers to adhere to skin well- remove sweat, hair, dirt etc.
Artefacts
-electrocardiographic alterations, not related to cardiac electrical activity
-lots of causes
-steps can be taken to reduce them
Causes of artefacts and what they look like
-loose electrode artefact- large rises and falls on graph
-wondering baseline artefact- baseline waves up and down caused by abnormal breathing eg. asthma, stress etc.
-muscle tremor artefact- more zig zags than normal, caused by muscle tremors eg. parkinsons, shivering
-electromagnetic interference- lots of electrical activity so no gaps between zig zags eg. reclining chairs
Placement of electrodes on limbs
Ride Your Green Bike
-Red= right arm
-Yellow= left arm
-Green= left foot (inside of ankle)
-Black= right foot (inside of ankle)
Why its called a 12 lead ECG
-lead doesn’t refer to the number of wires
-but refers to the number of views of the heart
-the limb electrodes produce 6 views- I,II,III, aVF, aVL, aVR
Chest (precordial) leads
V1- 4th intercostal space at the right border of the sternum
V2- 4th intercostal space on left of sternum
V3- midway between placement of V2 and V4
V4- 5th intercostal space at the midclavicular line (middle of clavicle)
V5- anterior axillary line on the same horizontal level as V4
V6- mid axillary line on same horizontal level as V4 and V5
Taking an ECG from start to finish
-informed consent
-chaperone/ ask others to leave?
-connect electrodes to leads
-remove clothing
-replace with blanket
-if possible patient should be semi-recumbent/ lying down
-prepare skin
-connect electrodes to patient
-encourage patient to relax
-press ‘record’ or ‘print’
