What is Acute Coronary Syndrome (ACS)?

From the Guidelines

Acute coronary syndrome (ACS) is a term that describes a group of conditions involving sudden, reduced blood flow to the heart muscle, which can lead to unstable angina, non-ST-elevation myocardial infarction (NSTEMI), or ST-elevation myocardial infarction (STEMI). The most recent and highest quality study, 1, provides the most up-to-date information on ACS. According to this study, ACS is a broad clinical presentation that ranges from cardiac arrest to patients who are already pain-free at the time of presentation.

Key Points:

• The leading symptom of ACS is acute chest discomfort, which can be described as pain, pressure, tightness, or burning, and may be accompanied by chest pain-equivalent symptoms such as dyspnea, epigastric pain, or pain in the left arm.
• The electrocardiogram (ECG) is used to differentiate between patients with ST-segment elevation and those without, with the former generally indicating an acute total or subtotal coronary occlusion.
• Patients with ACS may present with or without ST-segment elevation, and the diagnosis is ultimately made based on the presence or absence of serum cardiac markers such as troponin.
• Prompt recognition and treatment of ACS are crucial to prevent permanent heart damage or death, and treatment may involve medications such as aspirin, antiplatelet medications, anticoagulants, and pain relief with nitroglycerin, as well as procedures like angioplasty with stent placement to restore blood flow.
• Risk factors for ACS include smoking, high blood pressure, high cholesterol, diabetes, obesity, and family history of heart disease.

Symptoms and Diagnosis:

• Symptoms of ACS may include chest pain or pressure, shortness of breath, sweating, nausea, and lightheadedness.
• The diagnosis of ACS is based on a combination of clinical presentation, ECG findings, and serum cardiac markers.
• The ECG may show ST-segment elevation, ST-segment depression, or T-wave inversion, and serum cardiac markers such as troponin may be elevated.

Treatment and Management:

• Treatment of ACS depends on the type and severity of the condition, and may involve medications, procedures, or a combination of both.
• Medications may include aspirin, antiplatelet medications, anticoagulants, and pain relief with nitroglycerin.
• Procedures may include angioplasty with stent placement to restore blood flow.
• Secondary prevention and plans for long-term management begin early during the hospital phase of treatment.

From the FDA Drug Label

Non-ST-segment elevation acute coronary syndrome is defined as prolonged (≥10 minutes) symptoms of cardiac ischemia within the previous 24 hours associated with either ST-segment changes (elevations between 0.6 mm and 1 mm or depression >0. 5 mm), T-wave inversion (>1 mm), or positive CK-MB. This definition includes "unstable angina" and "NSTEMI" but excludes MI that is associated with Q waves or greater degrees of ST-segment elevation

Acute Coronary Syndrome (ACS) is defined as a condition characterized by prolonged symptoms of cardiac ischemia, which can be further classified into different types, including:

• Unstable Angina (UA): characterized by ST-segment changes or T-wave inversion
• Non-ST-Elevation Myocardial Infarction (NSTEMI): characterized by positive CK-MB ACS is a condition that requires prompt medical attention, and its management may involve the use of medications such as eptifibatide, as well as other interventions like percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) 2.

From the Research

Definition of Acute Coronary Syndrome

• Acute coronary syndrome (ACS) is characterized by a sudden reduction in blood supply to the heart 3
• It includes ST-segment elevation myocardial infarction (STEMI), non-STEMI (NSTEMI), and unstable angina 3, 4
• ACS is a common diagnosis in preclinical emergency medicine, summarizing the acute manifestations of coronary artery disease 5

Symptoms and Diagnosis

• Chest discomfort at rest is the most common presenting symptom of ACS, affecting approximately 79% of men and 74% of women 3
• Electrocardiography should be performed immediately (within 10 minutes of presentation) to distinguish between STEMI and non-ST-segment elevation ACS (NSTE-ACS) 3, 5
• High-sensitivity troponin measurements are the preferred test to evaluate for NSTEMI 3
• Elevated troponin levels without ST-segment elevation on electrocardiography suggest non-ST-segment elevation ACS 6

Treatment and Management

• Rapid reperfusion with primary percutaneous coronary intervention (PCI) within 120 minutes reduces mortality from 9% to 7% in patients with STEMI 3
• For patients with NSTE-ACS, prompt invasive coronary angiography and percutaneous or surgical revascularization within 24 to 48 hours are associated with a reduction in death from 6.5% to 4.9% 3
• Acetylsalicylic acid should be given to inhibit platelet aggregation in patients with ACS 5, 7
• Dual antiplatelet therapy, parenteral anticoagulation, statin therapy, beta-blocker therapy, and sodium-glucose cotransporter-2 inhibitor therapy are important management considerations for patients with ACS 6