Definition of Stable Angina
Stable angina (typical angina) is defined as substernal chest discomfort that meets all three of the following characteristics: (1) substernal chest discomfort of characteristic quality and duration, (2) provoked by exertion or emotional stress, and (3) relieved by rest and/or nitrates within minutes 1.
Clinical Characteristics
The 2013 ESC Guidelines provide a comprehensive framework for understanding stable angina through four key categories:
Location
The discomfort is typically located in the chest near the sternum, but may radiate to:
- Epigastrium to lower jaw or teeth
- Between shoulder blades
- Either arm extending to wrist and fingers 1
Character
Patients describe the sensation as:
- Pressure, tightness, or heaviness
- Strangling, constricting, or burning
- Many patients report "discomfort" rather than "pain" or "pressure" 1
Important clinical note: Shortness of breath may be the sole symptom of stable coronary artery disease and can accompany chest discomfort along with fatigue, faintness, nausea, burning, restlessness, or a sense of impending doom 1.
Duration
- Brief episodes: no more than 10 minutes in most cases, commonly just a few minutes
- Chest pain lasting only seconds is unlikely to be angina 1
Relationship to Triggers
Symptoms characteristically:
- Appear or worsen with increased exertion (walking uphill, against wind, in cold weather)
- Rapidly disappear within minutes when causal factors stop
- Worsen after heavy meals or upon waking in the morning
- May improve with continued exercise ("walk-through angina") or on second exertion ("warm-up angina")
- Respond rapidly to buccal or sublingual nitrates 1
Critical caveat: The angina threshold may vary considerably from day to day and even during the same day 1.
Classification Framework
The ESC guidelines distinguish three categories of chest pain 1:
- Typical angina: Meets all three defining characteristics
- Atypical angina: Meets only two of the three characteristics
- Non-anginal chest pain: Meets one or none of the characteristics
Atypical Presentations to Recognize
Vasospastic angina pattern: Pain resembling typical angina in location and character, responsive to nitrates but lacking precipitating factors. Starts at rest with low intensity, slowly intensifies, remains at maximum for up to 15 minutes, then slowly decreases. This pattern should alert you to possible coronary vasospasm 1.
Microvascular angina pattern: Pain of anginal location and quality triggered by exertion but occurring some time after exertion and may be poorly responsive to nitrates 1.
Severity Grading
The Canadian Cardiovascular Society classification grades angina severity 1:
- Class I: Angina only with strenuous/rapid/prolonged exertion; ordinary activity does not cause angina
- Class II: Slight limitation of ordinary activity (angina walking rapidly, climbing stairs after meals, in cold/wind, under stress, or climbing >1 flight of stairs)
- Class III: Marked limitation (angina walking 1-2 blocks or climbing stairs at normal pace under normal conditions)
- Class IV: Inability to carry on any physical activity without discomfort; angina may occur at rest