What are the criteria for ST elevation and depression in electrocardiography (ECG)?

From the Guidelines

ST elevation criteria include elevation of at least 2.5 mm in men < 40 years, 2 mm in men ≥ 40 years, or 1.5 mm in women in leads V2 –V3 and/or 1 mm in the other leads, while ST depression suggests myocardial ischemia, especially when the terminal T-wave is positive, with significant findings including ST-segment depression in leads V1 –V3. The criteria for ST elevation and depression in electrocardiography (ECG) are crucial for diagnosing myocardial ischemia and infarction. According to the 2017 ESC guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation 1, the ECG criteria are based on changes of electrical currents of the heart, with standard calibration of the ECG being 10mm/mV. Key points to consider when evaluating ST elevation and depression on an ECG include:

• ST-segment elevation measured at the J-point, which is considered suggestive of ongoing coronary artery acute occlusion in the following cases: at least two contiguous leads with ST-segment elevation
• Thresholds for ST elevation: 2.5 mm in men < 40 years, 2 mm in men ≥ 40 years, or 1.5 mm in women in leads V2 –V3 and/or 1 mm in the other leads
• ST-segment depression in leads V1 –V3, which suggests myocardial ischemia, especially when the terminal T-wave is positive
• The importance of recording right precordial leads (V3R and V4R) in patients with inferior MI to identify concomitant right ventricular infarction
• The use of leads V7 –V9 to confirm posterior MI, with ST-segment elevation 0.5 mm recorded in these leads. These criteria help differentiate between STEMI, which typically requires immediate reperfusion therapy, and other types of myocardial infarction, which may be managed differently 1.

From the Research

Criteria for ST Elevation and Depression in Electrocardiography (ECG)

The criteria for ST elevation and depression in electrocardiography (ECG) are crucial for diagnosing myocardial infarction.

• ST elevation is defined as an elevation of the ST segment by more than 1 mm in two or more contiguous leads on a 12-lead ECG 2.
• The diagnosis of ST-elevation myocardial infarction (STEMI) is typically made when there is ST-segment elevation in contiguous leads of a 12-lead electrocardiogram or with left bundle branch block 2.
• Transient STEMI is characterized by the resolution of ST-elevation and symptoms before revascularization, which occurs in up to 24% of patients presenting with STEMI 3.
• The mechanisms of spontaneous reperfusion in transient STEMI are unclear, but it is associated with less angiographic thrombus burden and spontaneous infarct artery reperfusion, resulting in less myocardial injury than STEMI 3.

Key Differences Between Transient and Persistent STEMI

• Transient STEMI patients have more cardiovascular risk factors, including more arterial disease and higher cholesterol values, compared to persistent STEMI patients 3.
• Angiographically, transient STEMI patients more often have no intracoronary thrombus and less often a high thrombus burden compared to persistent STEMI patients 3.
• Cardiac magnetic resonance imaging (CMR) reveals microvascular obstruction less frequently and smaller infarct size in transient STEMI patients, with a better preserved left ventricular ejection fraction 3.

Treatment Approaches for STEMI

• The treatment approach for STEMI should be individualized, taking into account the presence of multi-vessel disease and other factors 4.
• Single-vessel acute percutaneous coronary intervention (PCI) should be the default strategy, treating only the infarct-related artery during the acute phase of STEMI 4.
• Acute multi-vessel PCI can be justified only in exceptional patients with multiple critical and potentially unstable lesions 4.