What is the significance of ST segment elevation?

From the Guidelines

ST segment elevation is a critical indicator of acute myocardial infarction, particularly ST-elevation myocardial infarction (STEMI), and requires immediate reperfusion therapy to minimize morbidity and mortality. The significance of ST segment elevation lies in its ability to diagnose STEMI, which is defined as ST-segment elevation of greater than 0.1 mV in at least two contiguous precordial or adjacent limb leads, a new left bundle branch block, or a true posterior MI 1. According to the 2017 ESC guidelines, ST-segment elevation (measured at the J-point) is considered suggestive of ongoing coronary artery acute occlusion in the following cases: at least two contiguous leads with ST-segment 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 1.

Key Points to Consider

• The standard criteria for diagnosing STEMI include new ST elevation at the J point in at least two contiguous leads of ≥2 mm (0.2 mV) in men or ≥1.5 mm (0.15 mV) in women in leads V2-V3, or ≥1 mm (0.1 mV) in other contiguous chest leads or limb leads 1.
• Early recognition of these ECG changes is crucial as STEMI requires immediate reperfusion therapy, ideally primary percutaneous coronary intervention (PCI) within 90 minutes of first medical contact, or fibrinolytic therapy if PCI is not available within 120 minutes 1.
• It is essential to initiate ECG monitoring as soon as possible in all patients with suspected STEMI to detect life-threatening arrhythmias and allow prompt defibrillation if indicated 1.

Clinical Implications

• The goal is to minimize the time from the onset of symptoms until the initiation of reperfusion therapy, with a goal of fibrinolysis to begin less than 30 minutes from the time of the patient’s first contact with the health care system, or for balloon inflation for PCI to begin in less than 90 minutes 1.
• Patients with STEMI who present within 12 hours of symptom onset and do not have contraindications should receive immediate reperfusion therapy with fibrinolysis or PCI 1.
• If patients cannot reach a facility capable of PCI within the required 90 minutes, they should receive fibrinolysis unless contraindicated 1.

From the Research

Significance of ST Segment Elevation

The significance of ST segment elevation is a critical aspect of diagnosing and treating acute myocardial infarction (AMI). Key points related to ST segment elevation include:

• ST segment elevation is a key indicator of ST-elevation myocardial infarction (STEMI), which is the most acute manifestation of coronary artery disease 2.
• STEMI is associated with great morbidity and mortality, and early diagnosis and immediate reperfusion are essential to limit myocardial ischemia and infarct size 2.
• Primary percutaneous coronary intervention (PCI) is the preferred treatment for STEMI, and should be performed within 120 minutes of first medical contact 3, 2.
• The presence of ST segment elevation is used to guide treatment decisions, including the use of fibrinolysis therapy if PCI cannot be performed in a timely manner 2, 4.

Diagnostic and Treatment Implications

The presence of ST segment elevation has significant implications for diagnosis and treatment, including:

• Prehospital diagnosis of STEMI is critical to ensure timely treatment and improve outcomes 3.
• Patients with STEMI should receive immediate medical attention, including administration of acetylsalicylic acid, heparin, beta-blocker, and nitrates 4.
• The use of dual oral antithrombotic therapy, including clopidogrel and acetylsalicylic acid, is recommended for patients with STEMI 4.
• Treatment strategies for patients with multi-vessel disease and STEMI should be individualized, with single-vessel acute PCI being the default strategy 5.

Clinical Outcomes

The presence of ST segment elevation is associated with significant clinical outcomes, including:

• Patients with in-hospital STEMI have significant treatment delays and worse clinical outcomes compared to those who present via the emergency department 6.
• In-hospital STEMI patients have higher mortality rates and longer hospital stays compared to ED STEMI patients 6.
• Timely use of primary PCI is essential to improve outcomes for patients with STEMI, regardless of whether they present via the emergency department or develop STEMI while hospitalized for non-cardiac conditions 6.