The ST-Segment Basic EKG morphology

J point

The 3 most important things for you to remember are the following

1.The ST-segment: the flatter segment between the S-wave and the T-wave

2.The J point: the first inflection after the QRS, and the point at which the S-wave TURNS into

the flatter ST-segment

3.The TP-segment. This is the segment between the end of the T-wave and beginning of the

next p-wave. THIS IS THE MOST IMPORTANT SEGMENT FOR YOU TO IDENTIFY AS IT

WILL SERVE AS THE BASELINE FOR YOUR EKG. YOU WILL ALWAYS MEASURE ST-

SEGMENT ELEVATION IN RELATION TO THIS TP-SEGMENT!

TP SegmentJ point

The ST-Segment - Basic EKG morphology

J point

TP segment – baseline

J point – first “inflection” (curve) after the S wave;

junction of QRS with ST segment

TP SegmentJ point

In Summary:- The TP segment is your BASELINE for the EKG- The J point is your first inflection (or curve) after the S-wave; think of it as the junction

between the QRS with the ST segment

TP segment

p wave

The ST-Segment - Examples of J point and TP segment

J point

TP segment – baseline

J point – first “inflection” (curve) after the S wave; junction of QRS with ST segment

ON THE LEFT: identify your TP segment, which will be your baseline. Then, identify your J point (this helps you figure out where the beginning of the ST segment is). Once you’ve found the ST segment, compare it to the TP-segment. You’ll see that in the image on the left of the screen, the ST-segment is at the level of the TP-segment. THEREFORE, THERE IS NO ST-ELEVATIONON THE RIGHT: identify your j point, which is much easier to see in this example. The J point helps you figure out the beginning of the ST-segment. Then compare that with the TP-segment. Again, you’ll notice there IS no ST-segment elevation

The ST-Segment – Difference in height between J point & TP segment

Take a few seconds to identify the J-point, the ST-segment, and the TP-segmentTHEN, DECIDE: DOES THIS PATIENT HAVE ST-SEGMENT ELEVATION?

The ST-Segment – Difference in height between J point & TP segment

J point

TP segment

4mm

p wave

T wave

TP segment

QRSQRS

Find the J-point in lead V3. This will be the beginning of the ST-segment (which is up-sloping in this case).Now look at the end of the T-wave. Connect the flattest portion of this with the beginning of the next p-wave so you find your TP-segment.Notice that the ST-segment in this EKG is significantly elevated compared to the TP-segment. It is elevated by 4mm which is 4 small boxes. Each small box is 1mm.

This patient with chest pain has an anteroseptal STEMI – we’ll come back to what this means in just a moment.

J point

The ST-Segment

TP segment

Find the J-point, the ST-segment, and then the TP-segment.You’ll see that this patient with chest pain has 3mm elevation in leads V5 and V6 – This is a Lateral STEMI (we’ll come back to this terminology in just a moment)

J point

TP segment

7mm

p wave

The ST-Segment

TP segment

Find the J-point, the ST-segment, and then the TP-segment.You’ll see that this patient with chest pain has 7mm of elevation in lead II, which is an inferior STEMI (we’ll come back to this in a moment as well)

J pointp wave

The ST-Segment

TP segment

Find the J-point, the ST-segment, and then the TP-segment.You’ll see that this patient with chest pain has obvious elevation in multiple leads