What are the implications of ST elevations in precordial (electrocardiogram) leads?

From the Guidelines

ST elevations in precordial leads typically indicate an anterior myocardial infarction, which requires immediate medical attention, and the most recent guidelines from 2018 recommend initiating reperfusion therapy as soon as possible in patients with suspected STEMI 1. The precordial leads (V1-V6) monitor the anterior and lateral walls of the left ventricle, and ST segment elevations in these leads suggest acute coronary occlusion, most commonly of the left anterior descending artery. Some key points to consider in the diagnosis of STEMI include:

• A working diagnosis of STEMI must first be made, usually based on symptoms consistent with myocardial ischaemia and signs on a 12-lead electrocardiogram (ECG) 1
• ECG criteria for STEMI include ST-segment 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 1
• Treatment should begin with immediate administration of aspirin, antiplatelet therapy, and anticoagulation with heparin, and the definitive treatment is primary percutaneous coronary intervention (PCI) within 90 minutes of first medical contact 1
• If PCI is not available within this timeframe, fibrinolytic therapy should be considered with agents like alteplase if there are no contraindications 1 Other immediate measures include:
• Oxygen therapy if saturation is below 94%
• Pain relief with morphine (2-4mg IV)
• Nitrates (sublingual nitroglycerin 0.4mg) if blood pressure permits These interventions are crucial because anterior MIs carry significant mortality risk due to the large area of myocardium affected, with potential complications including heart failure, arrhythmias, and cardiogenic shock. It is also important to note that the 2018 guidelines recommend initiating ECG monitoring as soon as possible in all patients with suspected STEMI to detect life-threatening arrhythmias and allow prompt defibrillation if indicated 1.

From the Research

ST Elevation in Precordial Leads

• ST elevation in precordial leads is a key diagnostic feature of ST-segment elevation myocardial infarction (STEMI) 2, 3
• STEMI is caused by a complete thrombotic occlusion of an epicardial coronary vessel, resulting in myocardial ischemia and infarction 2
• The diagnosis of STEMI is typically made using electrocardiography, with ST elevation in precordial leads being a critical component of the diagnosis 3

Treatment of STEMI

• The treatment of STEMI typically involves prompt reperfusion therapy, either through primary percutaneous coronary intervention (PCI) or thrombolytic therapy 2, 3
• Antiplatelet therapy, including aspirin and clopidogrel, is also a crucial component of STEMI management, reducing the risk of recurrent myocardial infarction or death 4, 5
• The use of newer P2Y12 inhibitors, such as prasugrel and ticagrelor, has also been shown to be effective in reducing ischemic events in patients with STEMI 4

Diagnostic Strategies

• Traditional electrocardiography remains the cornerstone of STEMI diagnosis, with ST elevation in precordial leads being a key diagnostic feature 3
• Advances in imaging techniques, such as cardiac magnetic resonance imaging and coronary angiography, have also enhanced the accuracy of STEMI diagnosis and allowed for better risk stratification 3