12 Leads Flashcards
(49 cards)
Define J point
- junction between the end of the QRS complex and the beginning of the ST segment
- The point where the QRS stops and makes a sudden sharp change in direction
Define Ischemia and what it causes on the ECG
- lack of oxygen
- ST segment depression or T wave inversion
Define Injury in the context of a 12 lead
Prolonged Ischemia
ST segment elevation
Define Infarct in the context of a 12 lead
Prolonged injury results in death of tissue
May or may not see Q wave
What is the purpose of a 4 lead?
desgined to provide information needed to determine rate and underlying rhythm
designed to filter out artifact
What is the purpose of the 12 lead?
Designed to reproduce QRS, ST and T waveforms accurately
Designed to look more broadly at electrical activity
May result in greater artifact
Define Frequency Response
Term used to describe the breadth if the electrical spectrum viewed by the ECG monitor
What is the frequency response of a diagnostic quality ECG?
0.05 Hz to 150 Hz
What is the frequency response of a monitor quality ECG
0.5 Hz - 20-50 Hz
4 things that can influence the accuracy of an ECG
- lead placement
- frequency response
- calibration
- paper speed
Where do you place leads V1-V6
V1 - 4th ICS right of the sternum
V2 - 4th ICS, left of the sternum
V3 - Directly between leads V2 and V4
V4 - 5th ICS, left mid clavicular line
V5 - Level with V4 left axillary line
V6 - level with V5 at the left mid-axillary line
If the AVR lead is upright, what might be the cause?
Limbs leads are reversed
How many mm of elevation do you need in leads V1-V3 for it be classified as a STEMI?
2mm
How many mm of elevation does it need to be a STEMI in all leads except V1-V3?
1mm (one small box)
In order to qualify as an OMI there needs to ST elevation in how many leads?
2 anatomically continous
Define consectuive leads
- leads that look at the same portion of the heart (2, 3, aVF)
- Number continuously (V1,V2,V3,V4,V5.V6)
What does the right coronary artery supply?
- right ventricle
- inferior wall of LV
- SA and AV node
Posterior Descending Artery supplies
Posterior wall of left ventricle
Inferior wall of Right Ventricle
What does the left main coronary artery supply?
Extensive anterior
What does the left circumflex artery supply?
Lateral
Inferior (20%)
What does the left anterior descending artery supply?
Aneroseptal
What type of MI is known as a widowmaker?
Anterior MI
What leads would you see elevation in in a widow maker MI?
Septal, Anterior, and lateral leads
What are some common complications of a widowmaker MI?
Left Ventricular failure, CHF/Pulmonary edema, cardiogenic shock