Differential Diagnosis
Angina can usually be diagnosed from a proper history. When atypical features are present - such as prolonged duration (hours or days) or darting, knifelike pains at the apex or over the precordium - ischemia is less likely.

Anterior chest wall syndrome is characterized by sharply localized tenderness of intercostal muscles. Inflammation of the chondrocostal junctions, which may be warm, swollen, and red, may result in diffuse chest pain that is also reproduced by local pressure (Tietze’s syndrome). Intercostal neuritis (due to herpes zoster, diabetes mellitus, etc) also mimics angina.

Cervical or thoracic spine disease involving the dorsal roots produces sudden sharp, severe chest pain suggesting angina in location and “radiation” but related to specific movements of the neck or spine, recumbency, and straining or lifting.

Pain due to cervical or thoracic disk disease involves the outer or dorsal aspect of the arm and the thumb and index fingers rather than the ring and little fingers.

Peptic ulcer, chronic cholecystitis, esophageal spasm, and functional gastrointestinal disease may produce pain suggestive of angina pectoris. Reflux esophagitis is characterized by lower chest and upper abdominal pain after heavy meals, occurring in recumbency or upon bending over. The pain is relieved by antacids, sucralfate, H₂ receptor antagonists, or proton pump inhibitors. The picture may be especially confusing because ischemic pain may also be associated with upper gastrointestinal symptoms, and esophageal motility disorders may be improved by nitrates and calcium channel blockers. Assessment of esophageal motility may be necessary.

Degenerative and inflammatory lesions of the left shoulder and thoracic outlet syndromes may cause chest pain due to nerve irritation or muscular compression; the symptoms are usually precipitated by movement of the arm and shoulder and are associated with paresthesias.

Spontaneous pneumothorax may cause chest pain as well as dyspnea and may create confusion with angina as well as myocardial infarction. Even the ECG may resemble infarction because of changes in voltage from the pneumothorax. The same is true of pneumonia and pulmonary embolization. Dissection of the thoracic aorta can cause severe chest pain that is commonly felt in the back; it is sudden in onset, reaches maximum intensity immediately, and may be associated with changes in pulses. Other cardiac disorders such as mitral valve prolapse, hypertrophic cardiomyopathy, myocarditis, pericarditis, aortic valve disease, or right ventricular hypertrophy may cause atypical chest pain or even myocardial ischemia. Noninvasive testing and, in many cases, cardiac catheterization may be required to establish the diagnosis.