Intro to ECG Part 3 Flashcards
The junction between the __ and the___t is called the J point:
The junction between the QRS complex and the ST segment is called the J point:

J point?

This image shows J point elevation in lead III:
J point?

This image shows J point depression in lead V3:
J point?

After determining if the J point is elevated or depressed, analyze the shape of the J point. Here is an example of J point notching indicated by the blue arrow in lead II: AKA J WAVES
note
Analyze the J point for:
absolute position: it can be elevated or depressed
shape: it can be notched or slurred
Make sure that when you analyze an ECG, you pay close attention to the J point. It is a very small region on the ECG, but it plays an important role in helping you diagnose different causes of ST segment elevation. This is important because one cause of ST segment elevation is myocardial infarction, but myocardial infarction is not the only cause of ST segment elevation.

The J point can be thought of as the start of the ST segment. The ST segment should be evaluated after the J point is evaluated. Features that are important to analyze in the ST segment include:
absolute position: elevation vs. depression
slope: upsloping vs. downsloping vs. none
shape: flat vs. concave vs. convex

discuss absolute position and slope of the ST segment

This ECG has an upsloping ST segment and ST elevation The blue dotted line is the zero degrees baseline. The red dotted line is parallel with the ST segment and is angled/sloped upwards:
discuss the absolute position and slope of the St segment

example of ST depression with no sloping:
analyze the shape of the ST segment

This ECG shows a diffuse J point with ST segment elevation that is concave upward:
analyze the shape of the ST segment

The ST segment can also be concave down which can occur with ST depression.
analyze the shape of the ST segment

The opposite of concave up is convex up.
The T wave should be analyzed after the ST segment. The T wave should be analyzed for:
orientation: upgoing, downgoing (inverted) or biphasic
concordance with QRS
morphology (size and shape)

This is a biphasic T wave. It has 2 “phases”: this one has an initial downgoing deflection followed by an upgoing deflection.
cahracterize T wave

Here is another example of a biphasic T wave where the inverted portion is larger than the upright portion:
two causes of biphasic T waves

Biphasic waves are not normal. Biphasic T waves can be “up then down”, or “down, then up”.
There are 2 causes of biphasic T waves:
- Ischemia
- Hypokalemia
Inverted T waves are not normal. An exception to this rule is lead __
Inverted T waves are not normal. An exception to this rule is lead aVR
characterize T wave

inverted T wave
is this T wave discordant or concordant

discordant
is this T wave discordant or concordant

Concordant: both QRS and T wave are downgoing (this is common in aVR for normal ECG’s):
These peaked T waves in leads V3-5 are suggestive of __-___ ischemia:

These peaked T waves in leads V3-5 are suggestive of antero-lateral ischemia:
A T wave height is often correlated with the height of the QRS: a bigger QRS = a bigger T wave. T waves are __ in males and get __ with age.
A T wave height is often correlated with the height of the QRS: a bigger QRS = a bigger T wave. T waves are bigger in males and get smaller with age.
tall (peaked) T waves are seen in leads III and aVF, suggestive of ___ ischemia.

tall (peaked) T waves are seen in leads III and aVF, suggestive of inferior ischemia.
NOTE:
Flattened T waves are a non-specific finding, but may be caused by ischaemia or an electrolyte abnormality such as hypokalaemia. Flattened T waves due to ischemia are usually in a localized region of the ECG, while electrolyte abormalities cause T wave flattening in most or all leads.
Here is an example of flat T waves in V1 (blue arrows) and simultaneous ST depression in V4 and V5 from ischemia (red arrows):





