Acute Coronary Syndrome

• Left anterior descending (LAD) supplies

  • Anterior aspect of the left ventricle
  • Anterior aspect of the septum
• Left coronary artery becomes

  • Circumflex artery
  • Left anterior descending (LAD)
• Coronary Artery Anatomy

  • Right coronary artery (RCA)
  • Left coronary artery (LCA)
• Symptoms associated with chest pain in acute coronary syndrome

  • Pain radiating to the jaw or arms
  • Nausea and vomiting
  • Sweating and clamminess
  • A feeling of impending doom
  • Shortness of breath
  • Palpitations
• A silent myocardial infarction is when someone does not experience typical chest pain during acute coronary syndrome
• ECG Changes in Acute Coronary Syndrome

  ST-segment el
• Right coronary artery (RCA) supplies

  • Right atrium
  • Right ventricle
  • Inferior aspect of the left ventricle
  • Posterior septal area
• Symptoms should continue at rest for more than 15 minutes
• Acute coronary syndrome typically presents with central, constricting chest pain
• Patients with diabetes are particularly at risk of silent MIs
• Circumflex artery supplies

  • Left atrium
  • Posterior aspect of the left ventricle
• Types of acute coronary syndrome

  • Unstable angina
  • ST-elevation myocardial infarction (STEMI)
  • Non-ST-elevation myocardial infarction (NSTEMI)
• Artery

  • Heart Area
  • ECG Leads
• ECG Changes in Acute Coronary Syndrome - NSTEMI

  • ST segment depression
  • T wave inversion
  • Pathological Q waves
• Patients with diabetes are particularly at risk of silent myocardial infarctions
• Left anterior descending

  • Anterior
  • V1-4
• Right coronary artery

  • Inferior
  • II, III, aVF
• A rise in troponin is consistent with myocardial ischaemia as they are released from the ischaemic muscle tissue
• Assessment may involve repeated troponin tests, depending on the local policy (e.g., at baseline and 3 hours after the onset of symptoms)
• Troponin is a non-specific marker, meaning that a raised troponin does not automatically imply acute coronary syndrome. Alternative causes of a raised troponin include chronic kidney disease, sepsis, myocarditis, aortic dissection, and pulmonary embolism
• Patients with acute cardiac-sounding chest pain will have an ECG and troponin blood test as part of their workup. The results of the ECG and troponin will determine the type of acute coronary syndrome
• NSTEMI is diagnosed when there is a raised troponin, with either a normal ECG or other ECG changes (ST depression or T wave inversion)
• When a patient is presenting with chest pain and the troponin and ECG are normal, the diagnosis is either unstable angina or another cause, such as musculoskeletal chest pain
• When the patient is pain-free, but the pain occurred within the past 72 hours, they need to be referred to the hospital for same-day assessment, usually to be seen by the medical team
• Left coronary artery

  • Anterolateral
  • I, aVL, V3-6
• Pathological Q waves suggest a deep infarction involving the full thickness of the heart muscle (transmural) and typically appear 6 or more hours after the onset of symptoms
• ECG Changes in Acute Coronary Syndrome - STEMI

  • ST-segment elevation
  • New left bundle branch block
• Troponin results are used to diagnose an NSTEMI. They are not required to diagnose a STEMI, as this is diagnosed based on the clinical presentation and ECG findings
• Silent myocardial infarction occurs when someone does not experience typical chest pain during acute coronary syndrome
• Troponin

  A protein in cardiac muscle (myocardium) and skeletal muscle. Specific type, normal range, and diagnostic criteria vary based on different laboratories
• A high troponin or a rising troponin on repeat tests, in the context of suspected acute coronary syndrome, indicates an NSTEMI
• STEMI is diagnosed when the ECG shows either ST elevation or new left bundle branch block
• Circumflex

  • Lateral
  • I, aVL, V5-6
• Other Investigations in patients with suspected or confirmed acute coronary syndrome

  • Baseline bloods including FBC, U&E, LFT, lipids, and glucose
  • Chest x-ray to investigate for pulmonary oedema and other causes of chest pain
  • Echocardiogram once stable to assess the functional damage to the heart, specifically the left ventricular function
• Unstable angina is diagnosed when symptoms suggest ACS, the troponin is normal, and either a normal ECG or other ECG changes (ST depression or T wave inversion)
• Initial Management in patients presenting with symptoms of acute coronary syndrome can be remembered with the “CPAIN” mnemonic: Call an ambulance, Perform an ECG, Aspirin 300mg, Intravenous morphine for pain if required (with an antiemetic, e.g., metoclopramide), Nitrate (GTN)
• Thrombolysis

  Involves injecting a fibrinolytic agent. Fibrinolytic agents work by breaking down fibrin in blood clots. There is a significant risk of bleeding, which can make thrombolysis dangerous. Some examples of thrombolytic agents are streptokinase, alteplase, and tenecteplase
• Patients at medium or high risk

  Considered for early angiography with PCI (within 72 hours)
• Medications for PCI preparation

  • Aspirin
  • Prasugrel
• Medication for secondary prevention

  • Aspirin 75mg once daily indefinitely
  • Another Antiplatelet (e.g., ticagrelor or clopidogrel) for 12 months
  • Atorvastatin 80mg once daily
  • ACE inhibitors (e.g. ramipril) titrated as high as tolerated
  • Atenolol (or another beta blocker – usually bisoprolol) titrated as high as tolerated
  • Aldosterone antagonist for those with clinical heart failure (i.e. eplerenone titrated to 50mg once daily)