Acute Coronary Syndrome

What is acute coronary syndrome (ACS)?

A spectrum of conditions caused by acute myocardial ischemia due to plaque rupture and thrombosis.

What conditions fall under ACS?

• Unstable angina

• NSTEMI

• STEMI

What causes ACS?

Rupture of an atherosclerotic plaque leading to platelet aggregation and thrombus formation.

What is unstable angina?

Ischemic chest pain without troponin elevation and without ST-segment elevation.

What is NSTEMI?

Myocardial ischemia with elevated troponins but without ST-segment elevation.

What is STEMI?

Complete coronary occlusion causing ST-segment elevation and elevated troponins.

What are symptoms of ACS?

• Chest pain/pressure

• Radiation to arm/jaw

• Dyspnea

• Diaphoresis

• Nausea

What physical exam findings may occur in ACS?

• Diaphoresis

• Tachycardia

• Hypotension

• S3 gallop

What are high-yield risk factors for ACS?

• Hypertension

• Diabetes

• Smoking

• Hyperlipidemia

• Family history

• Age

• Male sex

What EKG findings occur in unstable angina?

• ST depression

• T-wave inversion

• Normal EKG possible

What EKG findings occur in NSTEMI?

• ST depression

• T-wave inversion

What EKG findings occur in STEMI?

• ST-segment elevation

• New LBBB

• Reciprocal changes

What is the significance of ST-segment elevation?

Indicates transmural ischemia due to complete coronary occlusion.

What is the significance of ST-segment depression?

Indicates subendocardial ischemia.

What cardiac biomarkers are used in ACS?

• Troponin I/T

• CK-MB

What is the most specific marker for myocardial injury?

Troponin

What is the timeline of troponin elevation?

Rises at 3–6 hours, peaks at 24 hours, remains elevated for 7–10 days.

What is the timeline of CK-MB elevation?

Rises at 3–12 hours, peaks at 24 hours, normalizes in 48–72 hours.

What imaging evaluates ACS?

• EKG

• Echocardiogram

• Coronary angiography

What is the definitive diagnostic test for ACS?

Coronary angiography.

What is the initial management of ACS?

• Aspirin

• Nitroglycerin

• Oxygen (if hypoxic

• Morphine (if needed

• Beta-blocker

• Statin

What antiplatelet therapy is used in ACS?

• Aspirin

• P2Y12 inhibitors (clopidogrel, ticagrelor)

What anticoagulation is used in ACS?

• Heparin

• Enoxaparin

What medications reduce mortality in ACS?

• Beta-blockers

• ACE inhibitors

• Statins

What is the treatment for STEMI?

Immediate reperfusion via PCI or fibrinolysis.

What is the preferred reperfusion strategy for STEMI?

PCI within 90 minutes

What fibrinolytics are used for STEMI?

• Alteplase

• Tenecteplase

What is the treatment for NSTEMI?

• Antiplatelets

• Anticoagulation

• Beta-blockers

• Statins

• Early invasive strategy if high risk

What is the treatment for unstable angina?

• Antiplatelets

• Anticoagulation

• Beta-blockers

• Statins

What medications should NOT be used in right ventricular infarction?

Nitrates (risk of hypotension).

What complications occur from ACS?

• Arrhythmias

• Heart failure

• Cardiogenic shock

• Papillary muscle rupture

• Ventricular septal rupture

• Free wall rupture

What arrhythmias occur after ACS?

• Ventricular fibrillation

• Ventricular tachycardia

• Atrial fibrillation

What is cardiogenic shock?

Severe pump failure causing hypotension and end-organ hypoperfusion.

What is the treatment for cardiogenic shock?

• Inotropes

• Vasopressors

• Revascularization

What is the classic triad of ACS?

• Chest pain

• EKG changes

• Elevated troponins

What EKG cluster strongly suggests STEMI?

• ST elevation

• Reciprocal depression

• New LBBB

What biomarker cluster strongly suggests NSTEMI?

• Elevated troponin

• ST depression

• T-wave inversion

What are high-yield differentials for ACS?

• Aortic dissection

• PE

• Pericarditis

• GERD

• Musculoskeletal pain