What is angina?

What is Angina?

Angina is a clinical syndrome characterized by substernal chest discomfort—typically described as pressure, tightness, or heaviness—that is provoked by exertion or emotional stress and relieved by rest and/or nitroglycerin within minutes. 1

Core Characteristics

Angina can be understood through four essential categories 1:

Location

• Primary site: Chest, near the sternum 1
• Radiation patterns: May be felt anywhere from the epigastrium to the lower jaw or teeth, between the shoulder blades, or in either arm extending to the wrist and fingers 1
• Atypical locations: Jaw, shoulder, back, or arms 1

Character and Quality

• Typical descriptors: Pressure, tightness, heaviness, strangling, constricting, or burning 1
• Important clinical note: Many patients do not describe "pain" or "pressure" but rather "discomfort"—directly asking about discomfort may be more revealing 1
• Associated symptoms: Shortness of breath (which may be the sole symptom), fatigue, faintness, nausea, burning, restlessness, or a sense of impending doom 1

Duration

• Brief episodes: No more than 10 minutes in the majority of cases, more commonly just a few minutes or less 1
• Key exclusion: Chest pain lasting only seconds is unlikely to be angina 1

Relationship to Triggers and Relief

• Provocative factors: Exertion (especially walking uphill, against wind, or in cold weather), specific activities, emotional stress, heavy meals, or first thing in the morning 1
• Relief pattern: Symptoms rapidly disappear within a few minutes when causal factors abate 1
• Nitroglycerin response: Buccal or sublingual nitrates rapidly relieve angina 1, 2
• Unique patterns: May be reduced with further exercise (walk-through angina) or on second exertion (warm-up angina) 1

Clinical Classification

Typical Angina (Definite)

Must meet all three characteristics 1:

• Substernal chest discomfort of characteristic quality and duration
• Provoked by exertion or emotional stress
• Relieved by rest and/or nitrates within minutes

Atypical Angina (Probable)

Meets two of the three typical characteristics 1

Special presentation: Pain resembling typical angina in location and character, responsive to nitrates but lacking precipitating factors—often starting at rest with low intensity, slowly intensifying, remaining at maximum for up to 15 minutes, then slowly decreasing; this pattern should alert clinicians to possible coronary vasospasm 1

Non-Anginal Chest Pain

Lacks or meets only one or none of the typical characteristics 1

Severity Grading: Canadian Cardiovascular Society Classification

1

• Class I: Ordinary activity does not cause angina (walking, climbing stairs). Angina occurs with strenuous, rapid, or prolonged exertion at work or recreation
• Class II: Slight limitation of ordinary activity. Angina on walking or climbing stairs rapidly, walking uphill, after meals, in cold/wind, under emotional stress, or walking more than 2 blocks on level ground or climbing more than one flight of stairs
• Class III: Marked limitation of ordinary physical activity. Angina on walking 1-2 blocks on level ground or climbing one flight of stairs under normal conditions at normal pace
• Class IV: Inability to carry on any physical activity without discomfort—angina syndrome may be present at rest

Underlying Pathophysiology

Angina results from myocardial ischemia due to temporary imbalance between myocardial oxygen supply and demand 1, 2:

• Most common cause: Atherosclerotic coronary artery disease with insufficient oxygen supply from fixed epicardial lesions 1, 3
• Alternative mechanisms: Microvascular dysfunction (inadequate response of resistance coronary vessels to vasodilator stimuli), coronary vasospasm, or other cardiac conditions including hypertrophic/dilated cardiomyopathy and aortic stenosis 1, 4

Important Clinical Caveats

• Variable threshold: The angina threshold may vary considerably from day to day and even during the same day 1
• Atypical presentations: Women and elderly patients often present with atypical symptoms such as nausea, vomiting, midepigastric discomfort, or sharp chest pain; in one study, 65% of women with ischemia presented with atypical symptoms 1
• Physical examination: Often normal or nonspecific in stable angina; during or immediately after ischemia, a third or fourth heart sound may be heard, and mitral insufficiency may be apparent, though these signs are elusive and non-specific 1
• Diagnostic pitfall: Pain that can be reproduced by palpation makes stable coronary artery disease less likely 1