Adding local short description: "Feature of an electrocardiogram", overriding Wikidata description "the ST segment connects the QRS complex and the T wave and has a duration of 0.080 to 0.120 sec"
{{Short description|Feature of an electrocardiogram}}
[[Image:SinusRhythmLabels.svg|right|thumb|Schematic representation of normal [[Electrocardiography|ECG]]]]
[[Image:SinusRhythmLabels.svg|right|thumb|Schematic representation of normal [[Electrocardiography|ECG]]]]
In [[electrocardiography]], the '''ST segment''' connects the [[QRS complex]] and the [[T wave]] and has a duration of 0.005 to 0.150 sec (5 to 150 ms).
In [[electrocardiography]], the '''ST segment''' connects the [[QRS complex]] and the [[T wave]] and has a duration of 0.005 to 0.150 sec (5 to 150 ms).
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==Interpretation==
==Interpretation==
* The normal ST segment has a slight upward concavity.
* [[File:ST segment elevation and depression.jpg|thumb|Illustration of ST segment elevation and depression ]]The normal ST segment has a slight upward concavity.
* Flat, downsloping, or depressed ST segments may indicate [[coronary ischemia]].
* Flat, downsloping, or depressed ST segments may indicate [[coronary ischemia]].
* [[ST elevation]] may indicate transmural [[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%.<ref>{{cite book |author=Sabatine MS|title=Pocket Medicine (Pocket Notebook) |publisher=Lippincott Williams & Wilkins |year=2000 |pages= |isbn=0-7817-1649-7 |oclc= |doi=}}</ref>
* [[ST elevation]] may indicate transmural [[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%.<ref>{{cite book |author=Sabatine MS|title=Pocket Medicine (Pocket Notebook) |publisher=Lippincott Williams & Wilkins |year=2000 |isbn=0-7817-1649-7 }}</ref>
* [[ST depression]] may be associated with subendocardial [[myocardial infarction]], [[hypokalemia]], or [[digitalis toxicity]].<ref>http://www.uab.edu/emig/yellow_book/yb_reading_ekg.htm</ref>
* [[ST depression]] may be associated with subendocardial [[myocardial infarction]], [[hypokalemia]], or [[digitalis toxicity]].<ref name="uab.edu 2010">{{cite web|date=2010-03-25|title=Reading an EKG|url=http://www.uab.edu/emig/yellow_book/yb_reading_ekg.htm|url-status=unfit|archive-url=https://web.archive.org/web/20100325192700/http://www.uab.edu/emig/yellow_book/yb_reading_ekg.htm|archive-date=2010-03-25|access-date=2021-11-04|website=uab.edu}}</ref>
==In fetal monitoring==
==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]].<ref>{{Cite journal | last1 = Mansano | first1 = R. Z. | last2 = Beall | first2 = M. H. | last3 = Ross | first3 = M. G. | doi = 10.1080/14767050601055279 | title = Fetal ST segment heart rate analysis in labor: Improvement of intervention criteria using interpolated base deficit | journal = Journal of Maternal-Fetal and Neonatal Medicine | volume = 20 | issue = 1 | pages = 47–52 | year = 2007 | pmid = 17437199 | pmc = }}</ref>
In [[fetal electrocardiography]], ST waveform analysis (sometimes abbreviated STAN) is used to get an indication of increasing levels of fetal [[base deficit]].<ref>{{Cite journal | last1 = Mansano | first1 = R. Z. | last2 = Beall | first2 = M. H. | last3 = Ross | first3 = M. G. | doi = 10.1080/14767050601055279 | title = Fetal ST segment heart rate analysis in labor: Improvement of intervention criteria using interpolated base deficit | journal = Journal of Maternal-Fetal and Neonatal Medicine | volume = 20 | issue = 1 | pages = 47–52 | year = 2007 | pmid = 17437199 | s2cid = 10815181 }}</ref>
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 ST 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 segments.
The ST segment represents the isoelectric period when the ventricles are in between depolarization and repolarization.
^Sabatine MS (2000). Pocket Medicine (Pocket Notebook). Lippincott Williams & Wilkins. ISBN0-7817-1649-7.
^"Reading an EKG". uab.edu. 2010-03-25. Archived from the original on 2010-03-25. Retrieved 2021-11-04.{{cite web}}: CS1 maint: unfit URL (link)
^Mansano, R. Z.; Beall, M. H.; Ross, M. G. (2007). "Fetal ST segment heart rate analysis in labor: Improvement of intervention criteria using interpolated base deficit". Journal of Maternal-Fetal and Neonatal Medicine. 20 (1): 47–52. doi:10.1080/14767050601055279. PMID17437199. S2CID10815181.
