The injury currents are not strong enough to be detected on leads with opposite angle of observation.There is no ECG lead with opposite angle of observation.However, reciprocal ST segment depressions may be missing. There are three explanations as to why reciprocal ST segment depressions may be absent: This is also consistent with the vector theory elevation in one lead should be recorded as depression in a lead with an opposite angle of observation. Importantly, reciprocal ST segment depressions strongly suggest transmural ischemia. These ST segment depressions are mirror images of the ST segment elevations, and they are seen in leads with a roughly opposite angle to the leads with ST elevations. Moreover, ischemic ST segment elevations are typically accompanied by reciprocal ST segment depressions. In STE-ACS ( STEMI) the level of the J point is typically close to the level of the T-wave apex (i.e the height difference between the J point and the apex of the T-wave is typically small). Other features of ischemic ST segment elevations To conclude, concave ST segment elevation is atypical of ischemia, but they do not rule out ischemia. Moreover, the ST segment may have a concave appearance if the T-wave is prominent (such as in hyperkalemia, early repolarization or even early phases of ischemia). There are plenty of cases of transmural ischemia presenting with concave ST elevations. This explains why guidelines require higher ST segment elevations in these leads (see criteria above). For example, roughly 90% of males aged <30 years display concave ST segment elevations in leads V2–V3. They occur in young, old, healthy and diseased individuals. Such ST segment elevations are extremely common in all populations. ST segment elevations with concave ST segmentĬoncave ST segment elevations pose a diagnostic challenge (Figure 1 B). It is wise to connect the patient to continuous ECG (ST) monitoring in order to detect such dynamics. Indeed, a dynamic (varying) ST segment is suggestive of myocardial ischemia. A patient may initially present with ST segment elevations which do not fulfill the ECG criteria, only to develop magnificent ST segment elevations a few minutes later. The ST segment elevations in ischemia are dynamic. Men & women V4R and V3R: ≥0,5 mm, except from men Women (any age): ≥1,5 mm in V2-V3 and ≥1 mm in all other leads.Men age Men age ≥40 years: ≥2 mm in V2-V3 and ≥1 mm in all other leads.New ST segment elevations in at least two anatomically contiguous leads:

Types of ST segment elevations on ECG.Ĭurrent guideline criteria for ischemic ST segment elevation:

Sinus rhythm with ivcd meaning