What is the definition of Non-ST-Elevation Myocardial Infarction (NSTEMI)?

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Last updated: February 11, 2025View editorial policy

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From the Guidelines

Non-ST-Elevation Myocardial Infarction (NSTEMI) is defined as a type of acute coronary syndrome (ACS) characterized by the absence of persistent ST-segment elevation on the electrocardiogram (ECG) and the presence of elevated cardiac biomarkers, such as troponin, indicating myocardial necrosis.

Key Characteristics of NSTEMI

  • The diagnosis of NSTEMI is based on the presence of elevated cardiac biomarkers, such as troponin, and clinical evidence of myocardial ischemia 1
  • NSTEMI is distinguished from unstable angina (UA) by the presence of elevated cardiac biomarkers, which indicate myocardial damage 1
  • The absence of persistent ST-segment elevation on the ECG is a key characteristic of NSTEMI, which differentiates it from ST-elevation myocardial infarction (STEMI) 1
  • NSTEMI can present with ST depression, transient ST-elevation, and/or prominent T-wave inversions on the ECG, but these findings are not required for diagnosis 1

Clinical Context

  • The diagnosis of NSTEMI requires interpretation of the ECG and cardiac biomarkers in the context of the patient's clinical presentation 1
  • The clinical presentation of NSTEMI can vary, but it is often characterized by ischemic chest pain and evidence of myocardial ischemia on the ECG or cardiac biomarkers 1
  • NSTEMI is a type of acute coronary syndrome, which also includes UA and STEMI, and is characterized by a spectrum of clinical presentations 1

From the Research

Definition of Non-ST-Elevation Myocardial Infarction (NSTEMI)

  • Non-ST-segment elevation myocardial infarction (NSTEMI) is defined as elevated cardiac biomarkers of necrosis in the absence of persistent ST-segment elevation in the setting of anginal symptoms or other acute event 2.
  • NSTEMI may result from an acute atherothrombotic event ('Type 1') or as the result of other causes of mismatch of myocardial oxygen supply and demand ('Type 2') 2.
  • It is characterized by an acute, critical increase in the already existing high microvascular resistance in addition to the subtotal coronary artery occlusion 3.

Key Characteristics of NSTEMI

  • NSTEMI represents the highest risk category of non-ST-segment elevation acute coronary syndromes (NSTEACS) 4.
  • It is a major cause of cardiovascular morbidity and mortality in the United States 4.
  • NSTEMI patients often have a higher comorbidity burden and diverse etiologies, which add complexity to therapeutic decision-making 2.

Diagnosis and Management of NSTEMI

  • Timely diagnosis and appropriate therapy are paramount to improve outcomes in NSTEMI patients 4.
  • Evidence-based treatment, with combination of antiplatelet and anticoagulant therapy, and with serious consideration of early coronary angiography and revascularization along with anti-ischemic medical therapy, is the mainstay of management for NSTEMI 4.
  • Applying in practice the American College of Cardiology/American Heart Association (ACC/AHA) guideline recommendations results in improved outcomes 4.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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