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| __NOTOC__
| | #Redirect [[ST interval#ST Elevation]] |
| {{SI}}
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| {{CMG}}
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| {{SK}} ST segment elevation; J point elevation; vaulting of the ST segments; current of injury
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| ==Overview==
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| ST elevations refers to a finding on an [[electrocardiogram]] that often reflects injury to the heart muscle or myocardium.
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| ==Pathophysiology==
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| [[ST segment]] corresponds to a period of ventrical [[Systole (medicine)|systolic]] [[depolarization]], when the cardiac muscle is contracted. Subsequent relaxation occurs during the [[Diastole|diastolic]] [[repolarization]] phase. The normal course of [[ST segment]] reflects a certain sequence of muscular layers undergoing repolarization and certain timing of this activity. When the cardiac muscle is damaged or undergoes a pathological process (e.g. [[inflammation]]), its contractile and electrical properties change. Usually, this leads to early repolarization, or premature ending of the [[Systole (medicine)|systole]].
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| The exact topology and distribution of the affected areas depend on the underlying condition. Thus, ST elevation may be present on all or some leads of ECG.
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| ==Causes==
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| ===Common Cuases===
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| *[[Acute MI]] or [[heart attack]]
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| *[[Early repolarization]]
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| *[[Left ventricular aneurysm]]
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| *[[Pericarditis]]<ref name="pmid18052017">{{cite journal |author=Tingle LE, Molina D, Calvert CW |title=Acute pericarditis |journal=Am Fam Physician |volume=76 |issue=10 |pages=1509–14 |year=2007 |month=November |pmid=18052017 |doi= |url=http://www.aafp.org/afp/20071115/1509.html}}</ref><ref name="pmid16228101">{{cite journal |author=Chew HC, Lim SH |title=Electrocardiographical case. ST elevation: is this an infarct? Pericarditis |journal=Singapore Med J |volume=46 |issue=11 |pages=656–60 |year=2005 |month=November |pmid=16228101 |doi= |url=http://www.sma.org.sg/smj/4611/4611me2.pdf}}</ref>
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| ===Causes in Alphabetical Order===
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| *[[Acute MI]] or [[heart attack]]
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| *[[Brugada syndrome]]
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| *[[Coronary vasospasm]]
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| *[[Early repolarization]]
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| *[[Hyperkalemia]] and this is known as a dialyzable current of injury
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| *[[Intracranial hemorrhage]]
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| *[[Left bundle branch block]]
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| *[[Left ventricular aneurysm]]
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| *[[Pericardiocentesis]] with contact of the needle with the myocardium creating a current of injury
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| *[[Pericarditis]]<ref name="pmid18052017">{{cite journal |author=Tingle LE, Molina D, Calvert CW |title=Acute pericarditis |journal=Am Fam Physician |volume=76 |issue=10 |pages=1509–14 |year=2007 |month=November |pmid=18052017 |doi= |url=http://www.aafp.org/afp/20071115/1509.html}}</ref><ref name="pmid16228101">{{cite journal |author=Chew HC, Lim SH |title=Electrocardiographical case. ST elevation: is this an infarct? Pericarditis |journal=Singapore Med J |volume=46 |issue=11 |pages=656–60 |year=2005 |month=November |pmid=16228101 |doi= |url=http://www.sma.org.sg/smj/4611/4611me2.pdf}}</ref>
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| *[[Prinzmetal's angina]]
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| *[[Pulmonary embolism]]
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| *[[Short QT syndrome]] (some variants)
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| *[[Vasospastic angina]]
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| ==Differentiating the Causes of ST Segment Elevation==
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| ====Myocardial Injury====
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| *The ST elevation is usually localized to an anatomic distribution that follows the coronary arteries (e.g. leads II,III, aVF).
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| *In the setting of myocardial injury, "reciprocal changes" representing ischemia in other leads or a mirror like effect of the ST elevation presenting as ST depression in other leads, may be present. For example, ST elevation in the anterior leads in acute MI may be accompanied by ST depression in the inferior leads.
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| *[[Prinzmetal's angina]] can cause transient ST elevation during chest pain.
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| *Contact of the needle can cause a "current of injury" and ST segment elevation during [[pericardiocentesis]].
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| ====Pericarditis====
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| *There is diffuse [[ST segment]] elevation (usually flat or concave up) together with [[PR segment depression]]. ST elevation reflects inflammation of the ventricular subepicardial layer and [[PR segment]] depression reflects inflammation of the atrial subepicardial layer.
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| *[[T wave inversion]] can be seen in [[pericarditis]] but usually not until the ST elevation has resolved, so *[[T wave inversion]] accompanying ST elevation is probably not due to [[pericarditis]]
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| ====Hyperkalemia====
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| [[Hyperkalemia]] may not affect all leads.
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| ====Ventricular Aneurysm====
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| *Ventricular aneurysm should be suspected if the ST segment elevation persists > 6 weeks after acute MI and if there is a wall motion abnormality on echocardiography.
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| ====Early Repolarization====
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| *"J point" elevation aka "[[early repolarization]]" is a concave-upward ST segment deflection.
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| *It is a normal variant
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| *Vaulting ST segment or J point elevation is a normal variant in leads V<sub>1</sub>-V<sub>3</sub>
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| ====Differentiating the Causes of ST Segment Elevation EKG Examples====
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| Shown below is an example of EKG illustrating ST elevation in various pathological states.
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| [[Image:Pathologic_ST_elevation.png|center|500px]]
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| ----
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| Shown below is an example of an EKG showing early repolarization ST elevation and normal ST elevation variants.
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| [[Image:Normal_ST_elevation.png|center|500px]]
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| ----
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| ==Related Chapters==
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| * [[ST segment]]
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| * [[ST depression]]
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| ==References==
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| {{Reflist|2}}
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| [[Category:Cardiology]]
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| [[Category:Electrophysiology]]
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