[[Image:normal_ST_elevation.png|thumb|300px|Examples of normal ST elevation]]
[[Image:pathologic_ST_elevation.png|thumb|300px|Examples of pathologic ST elevation. [[LVH]], [[LBBB]], [[Pericarditis]], [[Hyperkalemia]], [[Anterior AMI]] ]]
The most important cause of '''ST elevation''' is '''acute [[Ischemia]]'''. Other causes are <cite>Wang</cite><cite>Werf</cite>:
*[[Clinical Disorders#Pericarditis|Acute pericarditis]]: ST elevation in all leads except aVR
*[[Idioventricular Rhythm|Idioventricular rhythm]] including [[Pacemaker|paced rhythm]]
In a study by Otto et al. among 123 patients with chest pain and ST segment elevation of >1mm 63 patients did not have a myocardial infarction. Diagnoses in patients who did not have a myocardial infarction were [[LVH]] (33%) and [[LBBB]] (21%). <cite>Otto</cite> In daily practice this means that in these patients the diagnosis of myocardial infarction has to depend on other diagnostic means, such as laboratory tests, echocardiography and coronary angiography.
An important clue for the diagnosis of ischemia is the presence of [[Ischemia|reciprocal ST segment depression]].