Key Learning Points
Intervals and Segments
J Point Page 11
- The J-Point is located at the end of the QRS complex.
- The J-Point is a place in the cardiac cycle void of electrical activity.
- The J Point is a benchmark from which other ECG events are measured.
ST Segment and the Baseline Page 12
- The ST Segment lies between the J point, and the start of the T wave.
- The baseline is a flat spot on the ECG between the T and P wave devoid of depolarization or repolarization waves.
- The ST Segment's positive or negative shift from the baseline is measured, rather than its width as in other ECG components(a).
- Any positive or negative ST segment shift, above or below, the baseline can indicate a problem.
