unstable angina
๐น Unstable Angina – Overview
Unstable angina is a clinical syndrome under the spectrum of acute coronary syndromes (ACS), caused by reduced blood flow to the heart due to partial obstruction of a coronary artery. It is a medical emergency.
๐น Key Features
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Chest pain/discomfort at rest or with minimal exertion.
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New-onset angina (within the last 4–6 weeks, usually severe).
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Increasing frequency, duration, or severity of pre-existing angina (crescendo angina).
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Pain often lasts >20 minutes, not fully relieved by rest or nitroglycerin.
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May radiate to jaw, neck, left arm, or back.
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Associated symptoms: sweating, shortness of breath, nausea, palpitations, anxiety.
๐น Pathophysiology
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Rupture or erosion of an atherosclerotic plaque.
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Platelet aggregation and non-occlusive thrombus formation.
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Leads to intermittent myocardial ischemia without necrosis (troponin negative).
๐น Differentiation from Other ACS
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Unstable Angina (UA): No rise in cardiac biomarkers (troponin normal).
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NSTEMI: Biomarkers elevated (myocardial necrosis present).
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STEMI: Biomarkers elevated + ST elevation on ECG.
๐น ECG Findings
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Often normal or nonspecific.
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May show ST depression or T-wave inversion during pain episodes.
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No persistent ST elevation.
๐น Diagnosis
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Clinical history + risk factors (HTN, diabetes, smoking, dyslipidemia).
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ECG during pain and after.
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Cardiac biomarkers: negative in UA.
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Risk stratification scores (TIMI, GRACE).
๐น Management
Immediate Measures (MONA-B)
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Morphine (if pain persists).
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Oxygen (if SpO₂ < 90%).
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Nitrates (sublingual / IV).
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Aspirin (loading dose 300 mg).
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Beta-blockers (unless contraindicated).
Antithrombotic Therapy
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Dual antiplatelet therapy (DAPT): Aspirin + P2Y12 inhibitor (clopidogrel/ticagrelor).
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Anticoagulation: LMWH (enoxaparin), unfractionated heparin, or fondaparinux.
Additional
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Statins (high-intensity).
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ACE inhibitors/ARBs if LV dysfunction/diabetes/HTN.
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Revascularization (PCI/CABG) if high-risk.
๐น Prognosis
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UA carries a high risk of progression to MI if untreated.
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Early diagnosis and aggressive management improve outcomes.
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