acute%20coronary%20syndromes%20w_o%20persistent%20st-segment%20elevation
ACUTE CORONARY SYNDROMES W/O PERSISTENT ST-SEGMENT ELEVATION
Acute coronary syndromes refer to any constellation of clinical symptoms compatible with acute myocardial ischemia which may be life-threatening.
It encompasses unstable angina, non-ST-segment elevation myocardial infarction (NSTEMI) and ST-segment elevation myocardial infarction (STEMI).
Unstable angina is the ischemic discomfort that presents without persistent ST-segment elevation on ECG and without the presence of cardiac markers in the blood.
Non-ST-segment elevation myocardial infarction is diagnosed if cardiac markers are positive with ST-segment depression or with nonspecific or normal ECGs.
The patient typically presents with ischemic-type chest pain that is severe and prolonged and may occur at rest or may be caused by less exertion than previous episodes.

Introduction

Patients with suspected acute coronary syndrome must be evaluated quickly

  • Early, focused management of acute coronary syndrome reduces adverse events and improves outcomes
  • Pre-hospital department management includes:
    • Early activation of emergency medical service system (EMS)
    • Administration of Aspirin, oxygen, Nitroglycerin and Morphine (if needed)
    • If available, obtain 12-lead electrocardiogram (ECG)
  • Emergency department management includes:
    • Checking of vital signs, evaluating oxygen (O2) saturation (sat) and establishing intravenous (IV) access
    • Obtaining initial cardiac biomarker levels, chest x-ray and 12-lead ECG (if not yet done)

Definition

Acute Coronary Syndrome (ACS)

  • Any constellation of symptoms compatible with acute myocardial ischemia usually caused by sudden reduction in coronary blood flow

ACS encompasses the following:

  • Unstable Angina (UA)
    • Ischemic discomfort that presents without persistent ST-segment elevation on the ECG and without the presence of cardiac markers in the blood
  • Non-ST-Segment Elevation Myocardial Infarction (NSTEMI)
    • Diagnosed if cardiac markers are positive with ST-segment depression or with nonspecific or normal ECGs
  • ST-Segment Elevation Myocardial Infarction (STEMI)
    • Please refer to Myocardial Infarction with ST-Segment Elevation Disease Management Chart

Signs and Symptoms

  • Patient typically presents with ischemic-type chest pain as described below, except that the episodes may be more severe and prolonged, may occur at rest or may be caused by less exertion than previous episodes
  • Retrosternal chest pain
    • Pain is usually described as heaviness, pressure, tightness, cramping or burning in nature
    • Pain may occur at rest or during activity that may be associated with physical exertion or emotional stress
    • The pain which is usually central or in the left chest may radiate to the jaw, neck, left or both arms, back or shoulder
  • Atypical presentations are often observed in younger (25-40 years old) and older (>75 years old) patients, in women, and in patients with diabetes mellitus (DM), chronic renal failure or dementia
  • Atypical pattern: Pain develops in the arm, shoulder, wrist, jaw or back without occurrence in the chest
    • Discomfort that presents solely as jaw, neck, ear, arm or epigastric pain and is associated with exertion or stressor is relieved promptly with glyceryl trinitrate (GTN) should be considered equivalent to angina
  • Pain usually resolves in <5 minutes with rest and/or with use of sublingual GTN
    • Eg pain that occurs predominantly at rest, epigastric pain, recent onset of unexplainable indigestion, belching, stabbing chest pain, chest pain with some pleuritic features or increasing dyspnea
  • Accompanying symptoms may include: nausea and vomiting (N/V), dyspnea, diaphoresis, lightheadedness, abdominal (epigastric) pain, dizziness, fatigue, weakness and loss of consciousness
  • Common features of unstable angina:
    • Rest angina: Angina occurring at rest and prolonged, usually >20 minutes
    • New-onset severe angina: Patient usually has marked limitation on ordinary physical activity (angina occurs on walking 1-2 blocks on the level or climbing 1 flight of stairs under normal conditions and at a normal pace)
    • Increasing or crescendo angina: Previously diagnosed effort-related angina that has become distinctly more frequent, longer in duration or more easily provoked (by less effort than before)
    • Post-myocardial infarction (MI) angina

Risk Factors

  • Smoking
  • Dyslipidemia
  • Hypertension
  • Diabetes
  • History of coronary artery disease (CAD)
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