Definition and epidemiology
Angina pectoris is a clinical syndrome of chest pain or pressure resulting from an imbalance between myocardial oxygen supply and demand, most commonly due to atherosclerotic coronary artery disease (CAD).
It is classified as:
- Stable angina: predictable, exertion-induced, relieved by rest/nitrates, due to fixed atherosclerotic stenosis
- Unstable angina: new-onset, crescendo, or rest pain due to plaque rupture with thrombus formation without myocardial necrosis (part of acute coronary syndrome, ACS)
- Variant (Prinzmetal) angina: coronary vasospasm, often at rest, young patients, transient ST elevation
- Microvascular angina: angina with normal coronaries, due to small vessel dysfunction (more common in women)
CAD is a leading cause of morbidity and mortality worldwide. Prevalence of angina rises steeply with age and is higher in men until menopause, after which the gap narrows. Risk factors mirror those for atherosclerosis generally.
- Stable angina: exertional, resolves with rest/nitroglycerin within minutes, fixed stenosis
- Unstable angina: rest pain or crescendo pattern, no troponin elevation (unlike NSTEMI)
- Prinzmetal angina: coronary vasospasm, transient ST elevation, young patients, often smokers
- First-line stable angina workup: exercise ECG if baseline ECG normal and intermediate pretest probability
- All CAD patients get aspirin + statin regardless of LDL for secondary prevention
- Beta-blockers are first-line anti-anginal therapy for symptom control
- Left main or severe triple-vessel disease with diabetes favors CABG over PCI
- Microvascular angina (Cardiac Syndrome X): angina with normal coronary angiogram, more common in women
Etiology and risk factors
The dominant cause is atherosclerotic narrowing of one or more coronary arteries, reducing blood flow reserve during increased demand.
Major risk factors
- Hypertension
- Diabetes mellitus
- Dyslipidemia (elevated LDL, low HDL)
- Smoking
- Obesity and sedentary lifestyle
- Family history of premature CAD
- Age (men over 45, women over 55)
- Chronic kidney disease
Non-atherosclerotic causes
- Coronary vasospasm (Prinzmetal angina)
- Severe aortic stenosis or hypertrophic cardiomyopathy (increased demand, reduced supply)
- Severe anemia or hyperthyroidism (precipitating demand ischemia)
- Coronary microvascular dysfunction
Pathophysiology
Myocardial ischemia occurs when oxygen demand exceeds supply. Supply depends on coronary blood flow, which is limited by fixed stenosis (typically symptomatic once lumen narrowing exceeds about 70%) or by acute thrombus/plaque rupture (ACS).
In stable angina, a stable atherosclerotic plaque limits flow reserve; symptoms appear predictably when demand rises (exertion, emotional stress, cold exposure) and resolve with rest as demand falls.
In unstable angina, plaque rupture exposes thrombogenic material, triggering platelet aggregation and partial thrombus formation. This causes unpredictable, often rest-related ischemia without complete vessel occlusion or detectable myocardial necrosis (troponin remains negative, distinguishing it from NSTEMI).
Ischemia activates chemical mediators (adenosine, bradykinin) that stimulate cardiac afferent nerve fibers, producing the classic referred pain pattern (substernal, radiating to jaw, left arm, or back) via shared spinal cord pathways with somatic dermatomes.
Clinical features
- Substernal chest pressure, tightness, or heaviness, often described as a weight or band
- Radiation to the left arm, jaw, neck, or back
- Triggered by exertion, emotional stress, cold, or heavy meals (stable angina)
- Duration typically 2-10 minutes for stable angina; relieved within minutes by rest or nitroglycerin
- Associated symptoms: dyspnea, diaphoresis, nausea
- Unstable angina features: pain at rest, new-onset severe angina, or angina that is increasing in frequency, duration, or intensity (crescendo pattern)
- Atypical presentations (more common in women, elderly, diabetics): fatigue, dyspnea, epigastric discomfort, or no chest pain at all
- Physical exam is often normal between episodes; may reveal signs of risk factors (xanthelasma, hypertension) or transient S4 gallop during an episode
Diagnosis
Diagnosis combines clinical history, risk stratification, and objective testing for ischemia.
Initial workup
- ECG: often normal at rest in stable angina; may show ST depression or T-wave inversion during pain. New ST elevation suggests STEMI, not simple angina
- Troponin: normal in stable and unstable angina (elevated troponin reclassifies to NSTEMI)
- Lipid panel, HbA1c, CBC, renal function, thyroid function: evaluate risk factors and alternative causes
Stable angina workup
- Exercise ECG (stress test): first-line in patients with intermediate pretest probability and normal baseline ECG
- Stress echocardiography or nuclear perfusion imaging: for patients with abnormal baseline ECG or inconclusive exercise test
- Coronary CT angiography: good negative predictive value, useful in lower-risk patients
- Invasive coronary angiography: gold standard, reserved for high-risk patients or when noninvasive testing is positive/inconclusive
Suspected unstable angina / ACS
- Serial ECGs and troponins (to exclude NSTEMI/STEMI)
- Risk stratification scores (TIMI, GRACE) guide urgency of invasive strategy
- Early angiography if high-risk features present
Differential diagnosis
| Condition | Distinguishing feature |
|---|---|
| Myocardial infarction | Elevated troponin, often ST changes, longer duration pain |
| Pericarditis | Sharp pain, worse lying flat, improves sitting forward, friction rub |
| Aortic dissection | Sudden tearing pain radiating to back, pulse/BP asymmetry |
| Pulmonary embolism | Pleuritic pain, dyspnea, risk factors for VTE, hypoxia |
| GERD | Burning retrosternal pain, related to meals/lying down, antacid relief |
| Musculoskeletal pain (costochondritis) | Reproducible with palpation, no exertional pattern |
| Esophageal spasm | Can mimic angina closely, may respond to nitrates too |
| Panic attack/anxiety | Associated hyperventilation, paresthesias, situational trigger |
Management
Management addresses symptom relief, prevention of progression, and reduction of cardiovascular events. International guidelines (ACC/AHA, ESC) are broadly concordant.
Acute symptom relief
- Sublingual nitroglycerin for acute episodes
Anti-ischemic therapy (stable angina)
- Beta-blockers: first-line for symptom control, reduce heart rate and demand
- Calcium channel blockers: alternative or add-on, especially for vasospasm or beta-blocker intolerance
- Long-acting nitrates: added for persistent symptoms
- Ranolazine: option for refractory symptoms despite standard therapy
Secondary prevention (all patients with CAD)
- Aspirin (or clopidogrel if intolerant) for antiplatelet therapy
- Statin therapy regardless of baseline LDL, for plaque stabilization
- ACE inhibitor or ARB if diabetes, hypertension, or reduced ejection fraction present
- Aggressive risk factor modification: smoking cessation, blood pressure and glucose control, weight management, structured exercise program
Unstable angina / ACS pathway
- Admit, continuous cardiac monitoring
- Dual antiplatelet therapy (aspirin plus a P2Y12 inhibitor such as clopidogrel or ticagrelor)
- Anticoagulation (e.g., heparin) per ACS protocol
- Risk-stratify for early invasive strategy (coronary angiography) versus ischemia-guided approach
Revascularization
- Percutaneous coronary intervention (PCI): for suitable anatomy, especially single/double vessel disease or high-risk ACS
- Coronary artery bypass grafting (CABG): preferred for left main disease, severe triple-vessel disease, or diabetics with multivessel disease
- Choice between PCI and CABG depends on anatomy, comorbidities, and SYNTAX score; guideline recommendations vary slightly between societies for borderline cases
Complications and prognosis
- Progression to myocardial infarction
- Arrhythmias, including sudden cardiac death from ischemia-triggered ventricular tachyarrhythmia
- Heart failure from ischemic cardiomyopathy
- Reduced quality of life from recurrent symptoms
Prognosis in stable angina depends heavily on left ventricular function, extent of CAD, and control of risk factors; well-managed patients can have good long-term outcomes. Unstable angina carries a significant short-term risk of progression to MI or death and requires prompt risk stratification and treatment. Overall mortality has fallen substantially in recent decades due to earlier revascularization and widespread secondary prevention therapy.
Angina triggers remembered as the 4 E's: Exertion, Emotion, Eating (heavy meals), Exposure to cold.
Practice questions
1. A 58-year-old man presents with chest tightness that occurs after climbing two flights of stairs and resolves within 5 minutes of sitting down. He has a history of hypertension and smokes one pack of cigarettes daily. Resting ECG is normal. Which of the following is the most appropriate initial diagnostic test?
2. A 65-year-old woman with known stable angina reports that over the past week her chest pain has started occurring at rest and now takes longer to resolve with nitroglycerin. Troponin is negative and ECG shows no ST elevation. Which diagnosis best fits this presentation?
3. A 70-year-old man with stable angina and known triple-vessel coronary artery disease also has type 2 diabetes and an ejection fraction of 40%. Which management strategy is most appropriate for definitive revascularization?
Frequently asked questions
What causes angina?
Angina is caused by reduced blood flow to the heart muscle, most often from atherosclerotic narrowing of the coronary arteries. Less common causes include coronary artery spasm (Prinzmetal angina), severe aortic stenosis, hypertrophic cardiomyopathy, severe anemia, or microvascular dysfunction. The underlying problem is always a mismatch between the heart's oxygen demand and the blood supply it receives.
What are the first symptoms of angina?
The first symptom is usually a pressure, tightness, or heaviness in the center of the chest brought on by physical exertion or emotional stress. It can radiate to the left arm, jaw, neck, or back and is often accompanied by shortness of breath or sweating. Symptoms typically ease within a few minutes of resting or using nitroglycerin.
How is angina diagnosed?
Angina is diagnosed through a combination of clinical history, resting ECG, and a stress test such as exercise ECG, stress echocardiography, or nuclear perfusion imaging to demonstrate ischemia. Coronary CT angiography or invasive coronary angiography may follow depending on risk and test results. Blood tests, including troponin, help exclude a heart attack.
Is angina curable?
Angina itself is not usually 'cured' but can be effectively controlled with medications, lifestyle changes, and, when needed, revascularization procedures like angioplasty or bypass surgery. The underlying coronary artery disease is a chronic condition that requires ongoing risk factor management. Many patients achieve excellent long-term symptom control and quality of life with proper treatment.
Angina vs heart attack — what is the difference?
Angina is temporary chest pain from reduced blood flow that does not cause permanent heart muscle damage, while a heart attack (myocardial infarction) involves actual death of heart tissue, usually from a completely blocked artery. Angina pain typically resolves with rest or nitroglycerin within minutes, whereas heart attack pain is more prolonged and troponin blood levels are elevated only in a heart attack.
Key drugs
Related conditions and differentials
Sources and further reading
StatPearls (NCBI Bookshelf)MedlinePlusWHO ICD-10: I20
Educational content for medical students, prepared by the WhiteCoat Pro editorial team with AI assistance; every page is reviewed by a second AI model for factual errors. It is not medical advice and does not replace the product label, local guidelines or a clinician.