What is atypical chest pain?

What is Atypical Chest Pain?

The term "atypical chest pain" should be abandoned entirely and no longer used in clinical practice, as it is misleading and can result in inappropriate dismissal of potentially serious cardiac conditions. 1

Why This Term is Problematic

The 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR guidelines explicitly recommend against using "atypical" to describe chest pain because: 1

• It is not helpful in determining the actual cause of chest pain 1
• It is frequently misinterpreted as benign when it may represent serious pathology 1
• It creates diagnostic ambiguity - originally intended to indicate angina without typical features, but commonly misused to imply noncardiac origin 1

What Should Replace "Atypical Chest Pain"

Instead of "atypical," chest pain should be categorized as:

1. Cardiac - pain likely from myocardial ischemia 1
2. Possibly cardiac - intermediate probability 1
3. Noncardiac - pain unlikely from cardiac origin 1

Historical Definition (Now Obsolete)

Before this terminology was abandoned, "atypical chest pain" or "atypical angina" was traditionally defined as chest pain meeting only 2 out of 3 of the following characteristics: 1

• Substernal chest discomfort of characteristic quality and duration 1
• Provoked by exertion or emotional stress 1
• Relieved by rest and/or nitrates within minutes 1

The European Society of Cardiology (2013) also described atypical angina as chest pain resembling typical angina in location and character, responsive to nitrates but lacking precipitating factors, or pain that starts at rest and slowly intensifies (suggesting possible coronary vasospasm). 1

Clinical Reality: Why This Matters

Over half (51.7%) of Medicare patients with confirmed unstable angina had what was previously labeled "atypical" presentations, including dyspnea (69.4%), nausea (37.7%), diaphoresis (25.2%), syncope (10.6%), or pain in atypical locations. 2 These patients received less aggressive treatment with aspirin, heparin, and beta-blockers despite having genuine cardiac disease. 2

Subjective interpretation of chest pain "typicality" has poor discriminatory value (AUC 0.54) for diagnosing acute myocardial infarction in patients with nondiagnostic ECGs. 3 This means clinicians cannot reliably distinguish cardiac from noncardiac pain based on symptom characteristics alone.

Proper Approach to Chest Pain Characterization

Features Suggesting Higher Likelihood of Cardiac Origin:

• Quality: Pressure, squeezing, heaviness, tightness, gripping, or burning 1, 4
• Location: Central, substernal, or left-sided chest 1, 4
• Radiation: To left shoulder, arm, jaw, neck, or upper abdomen 1, 4
• Provocation: Exertion or emotional stress 1, 4
• Duration: Typically 2-10 minutes (not seconds, not hours) 1
• Relief: With rest or nitroglycerin within minutes 1

Features Suggesting Lower Likelihood of Cardiac Origin:

• Quality: Sharp, stabbing, fleeting (lasting only seconds) 1, 4, 5
• Characteristics: Pleuritic (worsens with inspiration), positional (changes with body position) 1, 4, 5
• Reproducibility: Point tenderness on palpation 1, 4, 5
• Duration: Less than 5 seconds or more than 30 minutes 5
• Provocation: Single movement of trunk/arm, local finger pressure, bending forward 5
• Location: Can be localized with one finger, shifting locations 1, 5

Critical Pitfalls to Avoid

• Never assume relief with nitroglycerin confirms cardiac origin - esophageal spasm and cervical root compression can also respond to nitroglycerin 4, 5
• Never assume lack of nitroglycerin relief excludes cardiac disease 4
• Women, elderly patients, and diabetics frequently present without "typical" symptoms - they may have predominantly dyspnea, nausea, or vague discomfort 4, 2
• Do not prematurely label pain as noncardiac without appropriate cardiac workup including ECG within 10 minutes and troponin measurement 4, 6

Practical Clinical Algorithm

When evaluating chest pain: 4, 6

1. Immediate triage based on likelihood of myocardial ischemia 1
2. ECG within 10 minutes of presentation 4, 6
3. Troponin measurement 4
4. Characterize as cardiac/possibly cardiac/noncardiac based on constellation of features, not single characteristics 1
5. If cardiac causes excluded, then pursue noncardiac workup (pulmonary, gastrointestinal, musculoskeletal, psychological) 4, 7