### Date : 2024-11-03 17:19 ### Topic : Acute Coronary Syndrome #cardiology ---- **Acute Coronary Syndrome (ACS)** is a spectrum of conditions associated with **sudden, reduced blood flow to the heart**, often due to **rupture of an atherosclerotic plaque** in a coronary artery. This leads to myocardial ischemia (reduced oxygen supply to the heart muscle) and, if untreated, can result in myocardial infarction (heart attack). ACS includes **unstable angina (UA)**, **non-ST elevation myocardial infarction (NSTEMI)**, and **ST-elevation myocardial infarction (STEMI)**. ### Types of Acute Coronary Syndrome ACS is classified based on the ECG findings and the presence of cardiac biomarkers: 1. **Unstable Angina (UA)**: - Symptoms of angina that are new, worsening, or occurring at rest, but without detectable damage to the heart muscle (no elevation in cardiac biomarkers like troponin). 2. **Non-ST Elevation Myocardial Infarction (NSTEMI)**: - Similar to unstable angina in presentation but with evidence of myocardial cell damage, as shown by elevated troponin levels. The ECG may show ST-segment depression or T-wave inversion but no ST elevation. 3. **ST-Elevation Myocardial Infarction (STEMI)**: - A complete blockage of a coronary artery leads to significant heart muscle damage, seen as ST-segment elevation on the ECG and elevated troponin levels. This is a medical emergency and requires urgent revascularization. ### Pathophysiology ACS is primarily caused by **rupture or erosion of an atherosclerotic plaque** in a coronary artery. Here’s how it unfolds: 1. **Plaque Rupture**: A plaque in the coronary artery ruptures, exposing its contents to the bloodstream. 2. **Thrombus Formation**: The body tries to repair the rupture by forming a blood clot (thrombus). This clot can partially or completely block the artery. 3. **Reduced Blood Flow**: Blocked blood flow leads to ischemia, causing symptoms of chest pain and, if prolonged, damage to the heart muscle. ### Risk Factors for Acute Coronary Syndrome ACS shares risk factors with other forms of coronary artery disease (CAD): - **Hypertension** - **Hyperlipidemia** (high cholesterol) - **Diabetes** - **Smoking** - **Obesity** - **Family History** of CAD - **Sedentary Lifestyle** - **Advanced Age** ### Symptoms of Acute Coronary Syndrome The symptoms of ACS can vary, but common presentations include: 1. **Chest Pain or Discomfort**: - Usually described as pressure, heaviness, or squeezing pain in the chest (may radiate to the arms, jaw, back, or neck). - **Not relieved by rest or nitroglycerin** in cases of myocardial infarction. 2. **Other Symptoms**: - **Shortness of Breath** - **Diaphoresis** (sweating) - **Nausea and Vomiting** - **Dizziness or Lightheadedness** - **Fatigue** (more common in women and older adults) ### Diagnosis of Acute Coronary Syndrome Diagnosing ACS requires a combination of clinical assessment, ECG, and blood tests: 1. **Electrocardiogram (ECG)**: - **STEMI**: ST-segment elevation in two or more contiguous leads, indicating a complete coronary occlusion. - **NSTEMI or UA**: ST-segment depression or T-wave inversion may be present, but there is no ST elevation. 2. **Cardiac Biomarkers**: - **Troponin**: The most specific and sensitive marker for myocardial injury. Elevated troponin indicates heart muscle damage, seen in both NSTEMI and STEMI. - **CK-MB**: An older biomarker for myocardial damage, less specific than troponin but sometimes measured. 3. **Additional Tests**: - **Chest X-ray**: To rule out other causes of chest pain, such as aortic dissection or pneumonia. - **Coronary Angiography**: May be performed urgently in STEMI to identify the blocked artery, or later in NSTEMI/UA to assess coronary anatomy and guide revascularization decisions. - **Echocardiography**: Used to assess wall motion abnormalities and heart function, especially in patients with STEMI. ### Treatment of Acute Coronary Syndrome The goals of treatment are to restore blood flow, relieve symptoms, and prevent complications like further ischemia or death. Treatment varies based on the type of ACS: #### 1. **General Medical Therapy** (for all ACS types) - **Antiplatelet Therapy**: - **Aspirin**: Given immediately to prevent further clotting. - **P2Y12 Inhibitors** (e.g., clopidogrel, ticagrelor): Added to aspirin for dual antiplatelet therapy. - **Anticoagulants**: - Medications like **heparin** or **low molecular weight heparin (e.g., enoxaparin)** reduce clot formation. - **Nitroglycerin**: Reduces chest pain by dilating coronary arteries and decreasing heart workload. - **Beta-blockers**: Decrease heart rate and myocardial oxygen demand, reducing ischemia. - **Statins**: High-dose statins (e.g., atorvastatin) help reduce cholesterol and stabilize plaques. - **Morphine**: Used for pain relief if nitroglycerin is not effective. #### 2. **Specific Treatments for STEMI** - **Immediate Reperfusion Therapy**: - **Percutaneous Coronary Intervention (PCI)**: The preferred treatment for STEMI, PCI (angioplasty and stenting) restores blood flow in the blocked artery. It should ideally be performed within 90 minutes of first medical contact. - **Thrombolytic Therapy**: If PCI is not available within the optimal time frame, clot-busting drugs (e.g., alteplase, tenecteplase) are used to dissolve the thrombus. This is used in settings without immediate access to PCI. #### 3. **Treatment for NSTEMI/Unstable Angina** - **Early Invasive Strategy**: - In high-risk patients (e.g., those with elevated troponins or high-risk ECG changes), early coronary angiography with possible PCI or CABG is often recommended. - **Ischemia-Guided Strategy**: - In lower-risk patients, medications are administered, and coronary angiography may be performed later if symptoms persist or worsen. ### Complications of Acute Coronary Syndrome Without prompt treatment, ACS can lead to several serious complications: 1. **Heart Failure**: Due to decreased heart muscle function, particularly in large infarcts. 2. **Arrhythmias**: Ventricular fibrillation, atrial fibrillation, or bradycardias can develop, especially in STEMI. 3. **Cardiogenic Shock**: Severe reduction in cardiac output due to extensive myocardial damage, leading to shock. 4. **Pericarditis**: Inflammation of the pericardium following a heart attack, known as **Dressler’s syndrome**. 5. **Myocardial Rupture**: Rare but life-threatening rupture of the ventricular wall, septum, or papillary muscles. ### Prognosis and Follow-up - **Prognosis**: With early intervention, particularly for STEMI patients, outcomes have significantly improved. However, the risk of recurrent ACS and progression to chronic heart failure remains. - **Follow-up**: Long-term management includes lifestyle modifications (e.g., smoking cessation, diet, exercise), medication adherence, and regular follow-up to monitor heart function and prevent recurrence. ### Summary - **Acute Coronary Syndrome (ACS)** refers to conditions involving sudden, reduced blood flow to the heart and includes unstable angina, NSTEMI, and STEMI. - **Diagnosis**: Based on ECG changes and cardiac biomarkers, mainly troponin. - **Treatment**: Antiplatelet therapy, anticoagulation, and reperfusion therapy (PCI or thrombolytics for STEMI). NSTEMI/UA may be treated with medications and angiography as needed. - **Complications**: Heart failure, arrhythmias, cardiogenic shock, and pericarditis. - **Prognosis**: Depends on the speed of treatment and the extent of myocardial damage. Early diagnosis and aggressive management of ACS are crucial to reduce mortality and prevent long-term complications. ### Reference: - ### Connected Documents: -