The ST Segment

5/26/2018 The ST Segment

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The ST Segment

The ST segment is the flat, isoelectric section of the ECG between the end of the S wave (the J

point) and the beginning of the T wave.

It represents the interval between ventriclar depolarisation and repolarisation.

The most important case of ST segment abnormalit! (elevation or depression) is m!ocardial

ischaemia " infarction.

Causes of ST segmentelevation

#cte m!ocardial infarction

Coronar! vasospasm ($rint%metal&s angina)

$ericarditis

'enign earl! repolarisation

eft bndle branch bloc

eft ventriclar h!pertroph!

*entriclar aner!sm

'rgada s!ndrome

*entriclar paced rh!thm
http://lifeinthefastlane.com/ecg-library/anterior-stemi/http://www.ncbi.nlm.nih.gov/pubmed/15293589http://lifeinthefastlane.com/ecg-library/basics/pericarditis/http://lifeinthefastlane.com/ecg-library/benign-early-repolarisation/http://lifeinthefastlane.com/ecg-library/basics/left-bundle-branch-block/http://lifeinthefastlane.com/ecg-library/basics/left-ventricular-hypertrophy/http://lifeinthefastlane.com/ecg-library/left-ventricular-aneursym/http://lifeinthefastlane.com/ecg-library/brugada-syndrome/http://lifeinthefastlane.com/ecg-library/pacemaker/http://cdn.lifeinthefastlane.com/wp-content/uploads/2011/01/waves-of-the-ecg.gifhttp://www.ncbi.nlm.nih.gov/pubmed/15293589http://lifeinthefastlane.com/ecg-library/basics/pericarditis/http://lifeinthefastlane.com/ecg-library/benign-early-repolarisation/http://lifeinthefastlane.com/ecg-library/basics/left-bundle-branch-block/http://lifeinthefastlane.com/ecg-library/basics/left-ventricular-hypertrophy/http://lifeinthefastlane.com/ecg-library/left-ventricular-aneursym/http://lifeinthefastlane.com/ecg-library/brugada-syndrome/http://lifeinthefastlane.com/ecg-library/pacemaker/http://lifeinthefastlane.com/ecg-library/anterior-stemi/


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+aised intracranial pressre

orpholog! of the Elevated ST segment

Myocardial infarction

#cte STEI ma! prodce ST elevation with either concave, conve- or obliel! straight

morpholog!.

ST segment morphology in other conditions

Pericarditis BER LBBB LV aneurysm Brugada

Patterns of ST elevation

Acute ST elevation myocardial infarction (STEMI)

Cases ST segment elevation and /0wave formation in contigos leads, either1

Septal (*203)

#nterior (*405)

ateral (I 6 a*, *708)
http://lifeinthefastlane.com/ecg-library/raised-intracranial-pressure/http://lifeinthefastlane.com/ecg-library/anterior-stemi/http://lifeinthefastlane.com/ecg-library/anterior-stemi/http://lifeinthefastlane.com/ecg-library/lateral-stemi/http://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/brugada1.pnghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/ventricular-aneursym.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/LBBB.pnghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/BER1.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/pericarditis.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/tombstone.pnghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/AMI-STE-4.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/ST-elevation-AMI.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/ST-elevation-AMI-2.pnghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/AMI-ST-elevation-3.pnghttp://lifeinthefastlane.com/ecg-library/raised-intracranial-pressure/http://lifeinthefastlane.com/ecg-library/anterior-stemi/http://lifeinthefastlane.com/ecg-library/anterior-stemi/http://lifeinthefastlane.com/ecg-library/lateral-stemi/


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Inferior (II, III, a*9)

+ight ventriclar (*2, *5+)

$osterior (*:0;)

There is sall! reciprocal ST depression in the electricall! opposite leads.

Follow the links above to find out more about the different STEMI patterns.

#nterolateral STEI

Coronary Vasospasm (Prinzmetals angina)

This causes a pattern of ST elevation that is very similar to acute STEMI i.e. localised STelevation with reciprocal ST depression occurring during episodes of chest pain. However, unlieacute STEMI the E!" changes are transient, reversi#le with vasodilators and not usually associated

with myocardial necrosis. They may #e impossi#le to differentiate on the E!".

$rin%metal


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$ericarditis cases widespread concave ST segment elevation with$+ segment depressionin

mltiple leads = t!picall! I, II, III, a*9, a* and *308. There is reciprocal ST depression and $+

elevation in leads a*+ and *2.

Pericarditis

Concave >saddlebac? ST elevation in leads I, II, a*, *508 with depressed $+

segments.

There is reciprocal ST depression and $+ elevation in a*+.

!enign Early "epolarisation

Cases mild ST elevation with tall T0waves mainl! in the precordial leads. Is a normal variant

commonl! seen in !ong, health! patients. There is often notching of the J0point = the >fish0hoo?

pattern.
http://lifeinthefastlane.com/ecg-library/basics/pr-segment/http://lifeinthefastlane.com/ecg-library/basics/pr-segment/http://cdn.lifeinthefastlane.com/wp-content/uploads/2011/10/BER.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2011/03/pericarditis.jpghttp://lifeinthefastlane.com/ecg-library/basics/pr-segment/


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'enign Earl! +epolarisation# There is slight concave ST elevation in the precordial and inferior leads

with notching of the $%point &the 'fish%hoo( pattern)

$eft !undle !ranc% !loc&

In left #undle #ranch #loc, the ST segments and T waves show 'appropriate discordance( i.e. they are directed opposite to the main vector of the *+S comple. This produces STelevation with upright T waves in leads with a negative *+S comple &dominant S wave),

while producing ST depression and T wave inversion in leads with a positive *+S comple&dominant + wave).

eft 'ndle 'ranch 'loc

@ote the ST elevation in leads with deep S waves = most apparent in *204.

#lso note the ST depression in leads with tall + waves = most apparent in I and a*.

$eft Ventricular 'ypertrop%y

-H causes a similar pattern of repolarisation a#normalities as -///, with ST elevation in the leadswith deep S%waves &usually 0%1) and ST depression2T%wave inversion in the leads with tall + waves&I, a-, 3%4).
http://cdn.lifeinthefastlane.com/wp-content/uploads/2011/02/[email protected]


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eft *entriclar A!pertroph!Severe -H with etremely deep S waves in 0%1 producing associated ST elevation &not due tomyocardial ischaemia).5lso note the ST depression and T%wave inversion in the lateral leads I, a- and 4 .

Ventricular Aneurysm

This is an E!" pattern of residual ST elevation and deep * waves seen in patients with previousmyocardial infarction. It associated with etensive myocardial damage and paradoical movement ofthe left ventricular wall during systole.

*entriclar #ner!sm

There is ST elevation with deep / waves and inverted T waves in *204.

This pattern sggests the presence of a left ventriclar aner!sm de to a prior

anteroseptal I.
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!rugada Syndrome

This in an inherited channelopath! (a disease of m!ocardial sodim channels) that leads to

paro-!smal ventriclar arrh!thmias and sdden cardiac death in !ong patients. The tell0

tale sign on the resting ECG is the >'rgada sign? = ST elevation and partial +''' in *203

with a >coved? morpholog!

'rgada s!ndrome

There is ST elevation and partial +''' in *203 with a coved morpholog! = the

>'rgada sign?.

Ventricular Paced "%yt%m

entricular pacing &with a pacing wire in the right ventricle) causes ST segment a#normalitiesidentical to that seen in -///. There is appropriate discordance, with the ST segment and T wavedirected opposite to the main vector of the *+S comple.
http://cdn.lifeinthefastlane.com/wp-content/uploads/2009/09/Brugada-type-1.jpg


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Seential atrial and ventriclar pacing

"aised intracranial pressure

+aised IC$ (e.g. de to intracranial haemorrhage, tramatic brain inBr!) ma! case ST

elevation or depression that simlates m!ocardial ischaemia or pericarditis. ore

commonl!, raised IC$ is associated with widespread, deep T0wave inversions (>cerebral T

waves?).

ST elevation de to tramatic brain inBr!

idespread ST elevation with concave (pericarditis0lie) morpholog! in a patient with

severe tramatic brain inBr!.
http://cdn.lifeinthefastlane.com/wp-content/uploads/2011/12/catechol-storm-raised-icp.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/AV-sequential-pacing-3.jpg


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Less common causes of ST segment elevation Pulmonary em#olism and acute cor pulmonale &usually in lead III)

5cute aortic dissection &classically causes inferior STEMIdue to +!5 dissection)

$%waves &hypothermia,hypercalcaemia)

Hyperalaemia

Sodium%channel #locing drugs &secondary to *+S widening)

6ollowing electrical cardioversion

!ardiac tumour

Mitral valvuloplasty

Pancreatitis 2 gall#ladder disease

Myocarditis

Septic shoc

5naphylais

Transient ST elevation after DC cardioversion from *9

J waves in h!pothermia simlating ST elevation

Causes of STdepression

Myocardial ischaemia 2 7STEMI

+eciprocal change in STEMI

Posterior MI

8igoin effect

Hypoalaemia

Supraventricular tachycardia

+ight #undle #ranch #loc

+ight ventricular hypertrophy

-eft #undle #ranch #loc &see a#ove)

-eft ventricular hypertrophy &see a#ove)

entricular paced rhythm &see a#ove)

orpholog! of ST depression
http://lifeinthefastlane.com/ecg-library/pe/http://lifeinthefastlane.com/ecg-library/basics/inferior-stemi/http://lifeinthefastlane.com/ecg-library/basics/inferior-stemi/http://lifeinthefastlane.com/ecg-library/basics/osborn-wave-j-wave-2/http://lifeinthefastlane.com/ecg-library/basics/hypothermia/http://lifeinthefastlane.com/ecg-library/basics/hypothermia/http://lifeinthefastlane.com/ecg-library/basics/hypercalcaemia/http://lifeinthefastlane.com/ecg-library/basics/hyperkalaemia/http://lifeinthefastlane.com/ecg-library/basics/tca-overdose/http://lifeinthefastlane.com/ecg-library/myocardial-ischaemia/http://lifeinthefastlane.com/ecg-library/myocardial-ischaemia/http://lifeinthefastlane.com/ecg-library/pmi/http://lifeinthefastlane.com/ecg-library/pmi/http://lifeinthefastlane.com/ecg-library/digoxin-effect/http://lifeinthefastlane.com/ecg-library/digoxin-effect/http://lifeinthefastlane.com/ecg-library/basics/hypokalaemia/http://lifeinthefastlane.com/ecg-library/svt/http://lifeinthefastlane.com/ecg-library/basics/right-bundle-branch-block/http://lifeinthefastlane.com/ecg-library/basics/right-ventricular-hypertrophy/http://lifeinthefastlane.com/ecg-library/basics/left-bundle-branch-block/http://lifeinthefastlane.com/ecg-library/basics/left-ventricular-hypertrophy/http://lifeinthefastlane.com/ecg-library/pacemaker/http://cdn.lifeinthefastlane.com/wp-content/uploads/2010/11/J-wave-1.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/DC-cardioversion.jpghttp://lifeinthefastlane.com/ecg-library/pe/http://lifeinthefastlane.com/ecg-library/basics/inferior-stemi/http://lifeinthefastlane.com/ecg-library/basics/osborn-wave-j-wave-2/http://lifeinthefastlane.com/ecg-library/basics/hypothermia/http://lifeinthefastlane.com/ecg-library/basics/hypercalcaemia/http://lifeinthefastlane.com/ecg-library/basics/hyperkalaemia/http://lifeinthefastlane.com/ecg-library/basics/tca-overdose/http://lifeinthefastlane.com/ecg-library/myocardial-ischaemia/http://lifeinthefastlane.com/ecg-library/pmi/http://lifeinthefastlane.com/ecg-library/digoxin-effect/http://lifeinthefastlane.com/ecg-library/basics/hypokalaemia/http://lifeinthefastlane.com/ecg-library/svt/http://lifeinthefastlane.com/ecg-library/basics/right-bundle-branch-block/http://lifeinthefastlane.com/ecg-library/basics/right-ventricular-hypertrophy/http://lifeinthefastlane.com/ecg-library/basics/left-bundle-branch-block/http://lifeinthefastlane.com/ecg-library/basics/left-ventricular-hypertrophy/http://lifeinthefastlane.com/ecg-library/pacemaker/


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ST depression can be either psloping, downsloping, or hori%ontal.

Aori%ontal or downsloping ST depression F.7 mm at the J0point in

3 contigos leads indicates m!ocardial ischaemia (according to the 200 Task

Force !riteria).

psloping ST depression is non0specific for m!ocardial ischaemia.

+eciprocal change has a morpholog! that resembles >pside down? ST

elevation.

ST depression in posterior I occrs in *204 and is associated with dominant +

waves and pright T waves.

ST depression upsloping (A) do*nsloping (!) %orizontal (C)

ST segment morp%ology in myocardial isc%aemia

"eciprocal c%ange
http://eurheartj.oxfordjournals.org/content/28/20/2525.fullhttp://eurheartj.oxfordjournals.org/content/28/20/2525.fullhttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/STD3.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/std5.pnghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/std4.pnghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/std6.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/horizontal-std2.pnghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/horizontal-STD.pnghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/ST-segment-paediatric.jpghttp://eurheartj.oxfordjournals.org/content/28/20/2525.fullhttp://eurheartj.oxfordjournals.org/content/28/20/2525.full


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ST elevation in III Reciprocal change in aVL

ST segment morp%ology in posterior MI

$atterns of ST depression

Myocardial Isc%aemia

ST depression de to sbendocardial ischaemiama! be present in a variable nmber of

leads and with variable morpholog!. It is often most prominent in the left precordial leads

*508. idespread ST depression with ST elevation in a*+ is seen in left main coronar!

arter! occlsion.

"#. ST depression localised to the inferior or high lateral leads is more likel$ to represent

reciprocal change than subendocardial ischaemia. The corresponding ST elevation ma$ be

subtle and difficult to see% but should be sought. This concept is discussed further here.
http://lifeinthefastlane.com/ecg-library/myocardial-ischaemia/http://lifeinthefastlane.com/ecg-library/lmca/http://lifeinthefastlane.com/ecg-library/lmca/http://hqmeded-ecg.blogspot.com/2010/08/st-depression-does-not-localize-2-cases.htmlhttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/pmI3.pnghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/pmi2.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/PMI-1.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/Reciprocal-change.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/reciprocal-change-2.jpghttp://lifeinthefastlane.com/ecg-library/myocardial-ischaemia/http://lifeinthefastlane.com/ecg-library/lmca/http://lifeinthefastlane.com/ecg-library/lmca/http://hqmeded-ecg.blogspot.com/2010/08/st-depression-does-not-localize-2-cases.html


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idespread sbendocardial ischaemia de to C# occlsion

"eciprocal C%ange

ST elevation dring acte STEI is associated with simltaneos ST depression in the

electricall! opposite leads1

Inferior STEI prodces reciprocal ST depression in a* (H lead I).

ateral or anterolateral STEIprodces reciprocal ST depression in III and a*9

(H lead II).

+eciprocal ST depression in *204 occrs with posterior infarction(see below).

+eciprocal ST depression in a* with inferior STEI
http://lifeinthefastlane.com/ecg-library/basics/inferior-stemi/http://lifeinthefastlane.com/ecg-library/basics/inferior-stemi/http://lifeinthefastlane.com/ecg-library/lateral-stemi/http://lifeinthefastlane.com/ecg-library/lateral-stemi/http://lifeinthefastlane.com/ecg-library/anterior-stemi/http://lifeinthefastlane.com/ecg-library/pmi/http://cdn.lifeinthefastlane.com/wp-content/uploads/2011/10/inf1.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2011/10/LMCA.jpghttp://lifeinthefastlane.com/ecg-library/basics/inferior-stemi/http://lifeinthefastlane.com/ecg-library/lateral-stemi/http://lifeinthefastlane.com/ecg-library/anterior-stemi/http://lifeinthefastlane.com/ecg-library/pmi/


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+eciprocal ST depression in III and a*9 with high lateral STEI

Posterior Myocardial Infarction

#cte posterior STEI cases ST depression in the anterior leads *204, along with

dominant + waves (>/0wave eivalent?) and pright T waves. There is ST elevation in the

posterior leads *:0;.

!lick hereto read more about posterior MI.

$osterior I
http://lifeinthefastlane.com/ecg-library/pmi/http://cdn.lifeinthefastlane.com/wp-content/uploads/2011/09/Posterior-MI.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2011/10/lateral-2.jpghttp://lifeinthefastlane.com/ecg-library/pmi/


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+igo,in Effect

Treatment with digo-in cases downsloping ST depression with a >sagging? morpholog!,

reminiscent of Salvador Dali&s mostache.

'ypo&alaemia

A!poalaemia cases widespread downsloping ST depression with T0wave

flattening"inversion, prominent waves and a prolonged / interval.

A!poalaemia

"ig%t ventricular %ypertrop%y

+*A cases ST depression and T0wave inversion in the right precordial leads *204.
http://cdn.lifeinthefastlane.com/wp-content/uploads/2011/03/ECG-exigency-013-1.jpghttp://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/salvador-dali-digitalis-effect.jpg


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+ight ventriclar h!pertroph!

"ig%t !undle !ranc% !loc&

+/// may produce a similar pattern of repolarisation a#normalities to +H, with STdepression and T wave inversion in 0%1.

+ight bndle branch bloc

Supraventricular tac%ycardia

Supraventricular tachycardia &e.g. 57+T) typically causes widespread hori9ontal STdepression, most prominent in the left precordial leads &:%4). This rate%related STdepression does not necessarily indicate the presence of myocardial ischaemia providedthat it resolves with treatment.
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#*0

nodal re0entr! tach!cardia
http://cdn.lifeinthefastlane.com/wp-content/uploads/2012/01/Orthodromic-AVRT-1.jpg

Documents

The ST Segment