ST segment: Difference between revisions
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It starts at the J point (junction between the QRS complex and ST segment) and ends at the beginning of the T wave. However, since it is usually difficult to determine exactly where the ST segment ends and the T wave begins, the relationship between the RT segment and T wave should be examined together. The typical ST segment duration is usually around 0.08 sec (80 ms). It should be essentially level with the PR and TP segment. |
It starts at the J point (junction between the QRS complex and ST segment) and ends at the beginning of the T wave. However, since it is usually difficult to determine exactly where the ST segment ends and the T wave begins, the relationship between the RT segment and T wave should be examined together. The typical ST segment duration is usually around 0.08 sec (80 ms). It should be essentially level with the PR and TP segment. |
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The ST segment represents the period when the ventricles are |
The ST segment represents the period when the ventricles are repolarized. It is isoelectric. |
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==Interpretation== |
==Interpretation== |
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Revision as of 04:42, 9 October 2013
In electrocardiography, the ST segment connects the QRS complex and the T wave and has a duration of 0.080 to 0.120 sec (80 to 120 ms).
It starts at the J point (junction between the QRS complex and ST segment) and ends at the beginning of the T wave. However, since it is usually difficult to determine exactly where the ST segment ends and the T wave begins, the relationship between the RT segment and T wave should be examined together. The typical ST segment duration is usually around 0.08 sec (80 ms). It should be essentially level with the PR and TP segment.
The ST segment represents the period when the ventricles are repolarized. It is isoelectric.
Interpretation
- The normal ST segment has a slight upward concavity.
- Flat, downsloping, or depressed ST segments may indicate coronary ischemia.
- ST elevation may indicate myocardial infarction. An elevation of >1mm and longer than 80 milliseconds following the J-point. This measure has a false positive rate of 15-20% (which is slightly higher in women than men) and a false negative rate of 20-30%.[1]
- ST depression may be associated with hypokalemia or digitalis toxicity.[2]
In fetal monitoring
In fetal electrocardiography, ST waveform analysis (sometimes abbreviated STAN) is used to get an indication of increasing levels of fetal base deficit.[3]
References
- ^ Sabatine MS (2000). Pocket Medicine (Pocket Notebook). Lippincott Williams & Wilkins. ISBN 0-7817-1649-7.
- ^ http://www.uab.edu/emig/yellow_book/yb_reading_ekg.htm
- ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 17437199, please use {{cite journal}} with
|pmid=17437199instead.