ST segment: Difference between revisions

In [[electrocardiography]], the '''ST segment''' connects the [[QRS complex]] and the [[T wave]] and has a duration of 0.080005 to 0.120150 sec (805 to 120150 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 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 segmentsegments.

The ST segment represents the isoelectric period when the ventricles are depolarized.in Itbetween isdepolarization isoelectricand repolarization.

* [[File:ST segment elevation and depression.jpg|thumb|Illustration of ST segment elevation and depression ]]The normal ST segment has a slight upward concavity.

* [[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 20-3020–30%.<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 depression]] may be associated with subendocardial [[nontransmural 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 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 | pmcs2cid = 10815181 }}</ref>