What are leads II III and aVF?
The arrangement of the leads produces the following anatomical relationships: leads II, III, and aVF view the inferior surface of the heart; leads V1 to V4 view the anterior surface; leads I, aVL, V5, and V6 view the lateral surface; and leads V1 and aVR look through the right atrium directly into the cavity of the …
What leads does a STEMI show in?
Classically, STEMI is diagnosed if there is >1-2mm of ST elevation in two contiguous leads on the ECG or new LBBB with a clinical picture consistent with ischemic chest pain. Classically the ST elevations are described as “tombstone” and concave or “upwards” in appearance.
Why does a STEMI cause ST elevation?
ST segment elevation occurs because when the ventricle is at rest and therefore repolarized, the depolarized ischemic region generates electrical currents that are traveling away from the recording electrode; therefore, the baseline voltage prior to the QRS complex is depressed (red line before R wave).
Which location of the Mi can be found with the lead II III and aVF?
When an inferior MI extends to posterior regions as well, an associated posterior wall MI may occur. The ECG findings of an acute inferior myocardial infarction include the following: ST segment elevation in the inferior leads (II, III and aVF)
How do you know if its a STEMI?
The diagnosis of STEMI is predominantly using the 12-lead ECG and cardiac enzymes. There is significant myocardial necrosis occurring in the setting of STEMI resulting in elevation of the cardiac enzymes (see review of Cardiac Enzymes for more details).
Is ST depression a STEMI?
De Winter T waves: a pattern of up-sloping ST depression with symmetrically peaked T waves in the precordial leads is considered to be a STEMI equivalent, and is highly specific for an acute occlusion of the LAD.
How many mm of ST depression is significant?
ST segment depression may be determined by measuring the vertical distance between the patient’s trace and the isoelectric line at a location 2-3 millimeters from the QRS complex. It is significant if it is more than 1 mm in V5-V6, or 1.5 mm in AVF or III.
How many mm of ST elevation is significant?
An ST elevation is considered significant if the vertical distance inside the ECG trace and the baseline at a point 0.04 seconds after the J-point is at least 0.1 mV (usually representing 1 mm or 1 small square) in a limb lead or 0.2 mV (2 mm or 2 small squares) in a precordial lead.
When to use new ST segment elevations for STEMI?
New ST segment elevations in at least two anatomically contiguous leads: Men age ≥40 years: ≥2 mm in V2-V3 and ≥1 mm in all other leads. Men age <40 years: ≥2,5 mm in V2-V3 and ≥1 mm in all other leads. Women (any age): ≥1,5 mm in V2-V3 and ≥1 mm in all other leads.
Why is lead aVL important in STEMI recognition?
This is known as the rule of proportionality. Because the ST-segment elevation is < 1 mm the computer is not giving the ***ACUTE MI SUSPECTED*** message. Note the downsloping ST-segment in lead aVL! That should make you very suspicious. There is also ST-depression in in the precordial leads. Do you see how the evidence is stacking up?
What does STEMI stand for in cardiac category?
Definition of a STEMI; ESC 2017 Guidelines, AHA/ACC 2013 Guidelines: ST-segment elevation (measured at J-point) ≥ 1mm in all leads except V2-V3 (amplified leads) In V2-V3, to be significant: Men ≥ 40: ≥ 2 mm; Men < 40: ≥ 2.5 mm [accounting for early repolarization in young men]
What causes a second degree AV block in inferior STEMI?
Up to 20% of patients with inferior STEMI will develop either second- or third-degree AV block. There are two presumed mechanisms for this: Ischaemia of the AV node due to impaired blood flow via the AV nodal artery. This artery arises from the RCA 80% of the time, hence its involvement in inferior STEMI due to RCA occlusion.