Unstable angina

A type of angina pectoris that is irregular and unpredictable

Overview

A depiction of a man experiencing chest pain, a common symptom of unstable angina.

Unstable angina is a condition characterized by unexpected chest pain, often occurring at rest, and is a form of acute coronary syndrome. It is considered a medical emergency because it can precede a myocardial infarction (heart attack). Unlike stable angina, which occurs predictably with exertion, unstable angina is unpredictable and can occur without any apparent trigger.

Pathophysiology

Unstable angina is primarily caused by the rupture of an atherosclerotic plaque in a coronary artery, leading to partial obstruction of blood flow. This results in insufficient oxygen supply to the myocardium, causing ischemia and chest pain. The condition is often associated with thrombosis and inflammation within the coronary arteries.

Symptoms

The primary symptom of unstable angina is chest pain or discomfort, which may radiate to the shoulder, arm, back, neck, or jaw. The pain is often described as a pressure or squeezing sensation. Other symptoms may include:

• Dyspnea (shortness of breath)
• Nausea
• Diaphoresis (sweating)
• Dizziness or lightheadedness

Diagnosis

Diagnosis of unstable angina involves a combination of clinical evaluation, electrocardiogram (ECG) findings, and biomarker analysis. Unlike a myocardial infarction, unstable angina does not typically result in elevated cardiac biomarkers such as troponin. However, ECG changes such as ST-segment depression or T-wave inversion may be present.

Treatment

The management of unstable angina involves both pharmacological and non-pharmacological strategies. Immediate treatment aims to relieve symptoms and prevent progression to myocardial infarction. Common treatments include:

• Nitrates to relieve chest pain
• Antiplatelet therapy such as aspirin and clopidogrel
• Anticoagulants like heparin
• Beta-blockers to reduce myocardial oxygen demand
• Statins to stabilize atherosclerotic plaques

In some cases, revascularization procedures such as percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) may be necessary.

Prognosis

The prognosis of unstable angina varies depending on the severity of the condition and the effectiveness of treatment. Early intervention and management can significantly improve outcomes and reduce the risk of progression to myocardial infarction.

Related pages

• Angina pectoris
• Myocardial infarction
• Coronary artery disease
• Acute coronary syndrome