ECG - STEMI and Ischaemia Flashcards
What artery is likley occluded in anterior STEMI
Left anterior descending artery
What artery is likley occluded in Inferior STEMI
Right Coronary Artery
What artery is likley occluded in Lateral STEMI
Circumflex Artery
What arteries may be occluded in Posterior STEMI
Circumflex or Right Cornary Artery
Criteria for Pathological Q Wave vs non-pathological
Q wave depth greater than 2 wee sqares (2mm)
Q wave criteria for indicating Cardiac Necrosis
Q wave greater than 2 wee squares
Q wave crosses more than 1 wee box horizontally
Q wave is 1/3 or greater than the size of the R wave.
Common Causes of Pathological Q
LVH
Stenosis
Hypertension
Cardiac Necrosis - Including Ischaemia.
Previous ischaemia from old MI
?Other stuff as well (less common)
Stages of a STEMI - Tissue
Acute Ischamia
Infarct
Cardiac Necrosis
ST Elevation mimimums to indicate STEMI
1mm or more in limb leads
2mm or more in chest leads
How long will a STEMI be active for before ST elevation decreases, what other changes also occur?
12 Hours minimum - up to several days
Pathological Q waves form
Inversion of T waves
Reduced ST Elevation
Stages of STEMI - Names
Hyperacute
Fully Evolved
Chronic Stabillised
CHD/ACS: 3 Presentations
STEMI (Full thickness)
NSTEMI (Partial thickness)
Unstable Angina
Why do we get pathological Q waves with Ischaemia
When myocardium die, the electrical impulse travels away from that area of tissue (and electrode) causing downward Q waves to show on the ECG.
What can inverted T waves indicate?
Old ischaemia
NSTEMI
Evolved or stabilised stage of STEMI
What are De Winters T waves/Hyperacute MI? What do they indicate?
Anterior STEMI (2% of cases)
T wave greater than 3/4 the size of the QRS
