Still unsurpassed as the foremost inferential sign of the acute coronary artery occlusion, the everlasting ST segment elevation heralds the acute coronary syndrome, prompting for an imperative and expeditious reperfusion therapy. The spatial grouping of the ST segment elevation presenting leads is conventionally regarded as a hint to nominate the culprit coronary artery and bespeaks its expected occlusion site, as a part of the necessary vital risk assessment. Besides  ST elevation  acute myocardial infarction (STEMI), a few special non-ST elevation electrocardiographic pictures also urge early reperfusion therapy, as being produced by an acute coronary artery occlusion too, hence their collective appellation as STEMI equivalents. Miscellaneous factors are able to undermine the diagnostic accuracy of the conventional electrocardiogram, either by a)limiting its sensitivity, or b)lowering its specificity for the ischaemic ST elevation (owing to scores of non-ischaemic causes). Whereas the cathlab must be activated on the spot for the patient afflicted with the acute coronary artery occlusion, the non-ischaemic ST elevation one should avoid  the exposure to the inborn haemorrhagic risk of a needless invasive procedure. 

Laurentiu Lucaci is cardiologist in the Clinic of Cardiology of the Institute of Cardiovascular Diseases of Iasi and lecturer at the Faculty of Medicine of the University of Medicine and Pharmacy of Iasi, in Romania. His areas of interest include electrocardiography, echocardiography, clinical cardiology.