ST elevation: Difference between revisions
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*[[Short QT syndrome]] (some variants) | *[[Short QT syndrome]] (some variants) | ||
==Differentiating the | ==Differentiating the Causes of ST Segment Elevation== | ||
ST elevation in | ===Myocardial Injury=== | ||
*The ST elevation is usually localized to an anatomic distribution that follows the coronary arteries (e.g. leads II,III, aVF). | |||
*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. | |||
*[[Prinzmetal's angina]] can cause transient ST elevation during chest pain. | |||
*Contact of the needle can cause a "current of injury" and ST segment elevation during [[pericardiocentesis]]. | |||
===Pericarditis=== | |||
*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. | |||
*[[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]] | |||
===Hyperkalemia=== | |||
[[Hyperkalemia]] may not affect all leads. | |||
===Ventricular Aneurysm=== | |||
*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. | |||
===Early Repolarization=== | |||
*"J point" elevation aka "early repolarization" is a concave-upward ST segment deflection. | |||
*It is a normal variant | |||
*Vaulting ST segment or J point elevation is a normal variant in leads V<sub>1</sub>-V<sub>3</sub> | |||
==See also== | ==See also== | ||
Revision as of 13:43, 23 September 2012
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
ST elevations refers to a finding on an electrocardiogram that often reflects injury to the heart muscle or myocardium.
Pathophysiology
ST segment corresponds to a period of ventrical systolic depolarization, when the cardiac muscle is contracted. Subsequent relaxation occurs during the 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.
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.
Causes
Common Cuases
Causes in Alphabetical Order
- Acute MI or heart attack
- Brugada syndrome
- Early repolarization
- Intracranial hemorrhage
- Left bundle branch block
- Left ventricular aneurysm
- Pericarditis[1][2]
- Pulmonary embolism
- Short QT syndrome (some variants)
Differentiating the Causes of ST Segment Elevation
Myocardial Injury
- The ST elevation is usually localized to an anatomic distribution that follows the coronary arteries (e.g. leads II,III, aVF).
- 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.
- Prinzmetal's angina can cause transient ST elevation during chest pain.
- Contact of the needle can cause a "current of injury" and ST segment elevation during pericardiocentesis.
Pericarditis
- 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.
- 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
Hyperkalemia
Hyperkalemia may not affect all leads.
Ventricular Aneurysm
- 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.
Early Repolarization
- "J point" elevation aka "early repolarization" is a concave-upward ST segment deflection.
- It is a normal variant
- Vaulting ST segment or J point elevation is a normal variant in leads V1-V3
See also
References
- ↑ 1.0 1.1 Tingle LE, Molina D, Calvert CW (2007). "Acute pericarditis". Am Fam Physician. 76 (10): 1509–14. PMID 18052017. Unknown parameter
|month=ignored (help) - ↑ 2.0 2.1 Chew HC, Lim SH (2005). "Electrocardiographical case. ST elevation: is this an infarct? Pericarditis" (PDF). Singapore Med J. 46 (11): 656–60. PMID 16228101. Unknown parameter
|month=ignored (help)