Acute Coronary Syndrome (ACS)

Related Subjects: | Anatomy and Physiology of the Coronary Arteries |Atherosclerosis |Ischaemic heart disease |Acute Coronary Syndrome (ACS): Complications |Acute Coronary Syndrome (ACS) |Assessing Chest Pain |ACS - General |ACS - STEMI |ACS - NSTEMI |ACS - GRACE Score |ACS - ECG Changes |ACS -Cardiac Troponins |ACS - Post MI arrhythmias |ACS: Right Ventricular Infarction

⚡ ST elevation changes everything! → Act FAST to restore coronary reperfusion (PCI or thrombolysis). 📉 Always check an ECG after ANY new chest pain. 👵 Large MIs can be silent in elderly/diabetics. 🫀 Early action saves lives → ensure defibrillator is available at bedside.

🚑 Immediate Assessment of Moderate–Severe Cardiac Chest Pain

📖 Introduction

• “Acute Coronary Syndrome” (ACS) = chest pain + myocardial ischaemia ± ECG changes.
• 🌡️ Stable angina ≠ ACS (but unstable angina often presents acutely).
• 📈 ECG separates STEMI (PCI/thrombolysis benefit) from NSTEMI (no benefit from lysis).
• 🧪 Troponin distinguishes Unstable Angina (normal) from NSTEMI (raised).

🔎 Acute Coronary Syndromes include

• 🟡 Unstable angina = symptoms + ECG changes + normal troponin
• 🟠 NSTEMI = symptoms + ECG changes + raised troponin
• 🔴 STEMI = symptoms + ST elevation + raised troponin

📊 NSTEMI vs STEMI

ℹ️ About

• 🫀 ACS = major cause of sudden cardiac death
• 🚨 STEMI → needs urgent reperfusion (PCI or thrombolysis)
• 💊 All ACS → antiplatelets, analgesia, oxygen, nitrates, early defib readiness

⚠️ Aetiology

• 🟢 Most STEMIs = occlusion of a major coronary artery
• 📍 Outcome depends on artery involved + how proximal + myocardium at risk
• ⏱️ “Time = muscle” → delay to PCI worsens prognosis
• 🛠️ PCI = mechanical reperfusion | Thrombolysis = pharmacological reperfusion

🧬 Pathophysiology

• 🔓 Plaque rupture/erosion → thrombus forms
• 🩸 May embolise → distal ischaemia
• ⛔ Vessel occlusion → myocardial ischaemia/infarction

📑 Classification of MI

Not all raised troponins = plaque rupture. ⚠️ Consider Type 2 “secondary myocardial injury”.

⚠️ Risk Factors

• 👨 >40 yrs, 👩 >50 yrs
• 🧬 Family history of premature IHD
• 🚬 Smoking, 🍔 dyslipidaemia, 💉 diabetes, ⬆ BP hypertension

🩺 Clinical Presentation

• 🚨 Chest/arm/jaw pain at rest = red flag
• 😰 Pale, sweaty, cold peripheries
• 👵 Elderly/diabetics → atypical (dyspnoea, confusion, syncope, epigastric pain)
• 🫀 Exam: hypotension, S3, new murmurs, JVP ↑, pulmonary oedema

Summary Table - Complications of Acute Coronary Syndrome (ACS)

Teaching Commentary 🧠

Complications of ACS follow a predictable timeline: - Minutes–hours: arrhythmias, shock. - Days: mechanical rupture syndromes. - Weeks: pericarditis, Dressler’s. Careful monitoring in CCU is essential, and early recognition saves lives. Always think in categories (electrical, mechanical, pump, systemic) for exams and clinical safety.

🧪 Investigations

• ECG: 🚦 Always repeat with new pain
• Troponin T/I: 🧬 high-sensitivity rules MI in/out
• Echo: wall motion, LV function
• Other labs: FBC, U&E, lipids, glucose
• Consider CT aorta/PE if atypical

💊 Secondary Prevention

• 🛡 Beta-blockers (unless contraindicated)
• 💊 High-dose statin (Atorvastatin 80 mg)
• 💊 ACEi/ARB (start once stable)
• 🌀 Eplerenone (if post-MI LVSD/HF)
• 💊 PPI if high GI bleed risk on DAPT

📚 Reference

• SIGN 148: Acute Coronary Syndrome (2016)

Cases - Acute Coronary Syndrome (ACS) & Complications

• Case 1 - NSTEMI with CKD 🧪: A 68-year-old man with diabetes and CKD stage 4 presents with chest pain at rest and troponin rise. ECG: ST depression in V4–V6. Diagnosis: NSTEMI. Issue: Contrast-induced nephropathy risk during angiography. Management: Aspirin + clopidogrel, fondaparinux; hydrate before angiography; minimise contrast load.
• Case 2 - STEMI with Cardiogenic Shock ❤️: A 60-year-old woman presents with acute chest pain and hypotension (BP 75/40). ECG: anterior STEMI. Echo: severe LV systolic dysfunction. Diagnosis: STEMI complicated by cardiogenic shock. Management: Immediate PCI (preferred) or thrombolysis; cautious fluids; inotropes (dobutamine); consider IABP or mechanical support.
• Case 3 - ACS with Bleeding Risk 🩸: A 75-year-old man with a recent peptic ulcer bleed presents with NSTEMI. Troponin elevated, ECG: dynamic T-wave inversion. Issue: Antiplatelet therapy vs high GI bleed risk. Management: Aspirin essential; add PPI; weigh DAPT vs bleeding risk; liaise with gastro + cardiology; angiography with careful anticoagulation strategy.
• Case 4 - Post-MI Arrhythmia ⚡: A 58-year-old man 2 days after inferior STEMI develops sudden palpitations and collapse. ECG: sustained VT. Diagnosis: Ventricular tachycardia complicating acute MI. Management: Immediate DC cardioversion if unstable; amiodarone IV if stable; secondary prevention with ICD if EF remains low.
• Case 5 - Mechanical Complication (Papillary Muscle Rupture) 💔: A 70-year-old woman, 5 days post-MI, develops acute pulmonary oedema and a new pansystolic murmur. Echo: flail mitral leaflet with severe MR. Diagnosis: Papillary muscle rupture causing acute severe MR post-MI. Management: Urgent surgical repair/replacement; stabilise with diuretics, inotropes, and possible IABP as bridge.

Teaching Commentary 🧠

ACS complications can be divided into: - Early electrical → arrhythmias (VT, VF, AV block). - Mechanical → papillary muscle rupture, ventricular septal rupture, free wall rupture. - Pump failure → cardiogenic shock, LV dysfunction. - Other issues → bleeding risk (dual antiplatelets + anticoagulation), renal impairment, contrast nephropathy. Management is always: ABCDE, oxygen if hypoxic, antiplatelets, anticoagulation, reperfusion (PCI/thrombolysis for STEMI), risk stratification for NSTEMI. Complications highlight why close monitoring in CCU is essential during the first days post-ACS.