Key messages

• Cardiac ischemia (myocardial infarction or unstable angina) is a common cause of chest pain in men from middle life onwards.

• A coronary origin for chest pain in a premenopausal woman who has no family history of early ischemic heart disease is unusual, particularly if the cholesterol is normal and she does not smoke.

• Exclusion of acute myocardial infarction and unstable angina is a major goal, but this may require several hours of observation, serial ECGs, and measurement of cardiac enzymes.

The prevalence of coronary disease in Western males in late middle life and beyond is such that coronary artery disease is highly likely in any older man (over 55 years) who has any type of chest pain. The absence of ECG changes at the time of review may only indicate temporary resolution of the ischemia. At the other end of the spectrum, a non-smoking woman who is within 10 years of the menopause, who has no family history of ischemic heart disease, and has atypical pain is very unlikely to have significant coronary disease. Non-cardiac causes of chest pain have to be considered, but exclusion of unstable (pre-infarction) angina or myocardial infarction is the major goal. Short-lasting chest pain at rest in a patient of either gender, associated with any ECG abnormalities (e.g. transient ST depression, T inversion, or ST elevation), should be treated as unstable angina, and the patient should be admitted for treatment guided by local policy (i.e. conservative or investigative).

Acute chest pain is the presenting symptom of a number of life-threatening conditions, of which myocardial infarction is the most common. In up to 60 per cent of patients, myocardial infarction will not be recognized as such; in half of these it can be considered as silent, with no event recalled that could be associated with sudden coronary occlusion. Myocardial infarction is usually associated with acute injury potentials (ST segment elevation) seen on ECG. Sometimes, particularly in small inferior or evolving posterior myocardial infarctions, these ECG changes may be subtle and not immediately appreciated. Some young people, most often of Afro-Caribbean origin, have a high ST segment take-off which, in the presence of chest pain, may lead to confusion with myocardial infarction. The ST segment usually has a normal slope with a T wave that may appear somewhat peaked. Chest pain in these cases may be quite atypical, and the patient does not have the anxiety and apprehension which frequently accompany myocardial infarction. In these circumstances, there is time to consider carefully and repeat the ECG at 30-min intervals over the next hour or so. This will often reassure that there is no evolution of infarct-related changes. The benefits of thrombolysis are seen in those with ST segment elevation or left bundle branch block, and so there is time for procrastination when the picture is less clear.

Pulmonary embolism and aortic dissection can also present with profound symptoms. Myocardial infarction due to coronary dissection may also complicate aortic dissection. In the absence of an ECG typical of acute myocardial infarction in a patient presenting with acute chest pain, associated symptoms and signs and the results of other immediate investigations (e.g. chest radiography, blood gases, troponin T) will help in the differentiation ( Table 1).

Table 1 Differential diagnosis of chest pain

If there is a suspicion of aortic dissection, thrombolysis should be deferred. There is little to choose between spiral CT scanning, magnetic resonance imaging, experienced transesophageal echocardiography, and aortography with respect to both sensitivity and specificity of diagnosis of aortic dissection. The 24-h availability of one modality of investigation is the essential factor, as are facilities for safe escorted transfer of the patient to a referral center if such an investigation and surgical intervention are required. Pulmonary embolism can occur in patients at low risk of ischemic heart disease (e.g. premenopausal women). Any predisposing factor (obesity, immobility, oral contraceptive pill use, recent parturition or surgery, previous history of thromboembolic disease) should raise suspicion of this diagnosis.

When considering pericarditis, widespread convex ST segment elevation and posture-related changes in pain severity, as well as a sharp scratchy quality to the pain, are typical. The precordium should be auscultated with the patient in different positions (e.g. sitting forward and recumbent) in an attempt to elicit a rub. A two-dimensional echocardiogram may be useful, confirming normal left ventricular function and sometimes demonstrating a small amount of pericardial fluid.

The patient with pneumonia is often toxic and unwell, may have a fever, and may be hypoxemic. A raised neutrophil count may not always be seen, as overwhelming sepsis can suppress the acute marrow response.

Acute costochondritis is associated with exquisite chest tenderness, tightly localized to costochondal joints but often radiating along the intercostal nerve desmosomes.

Reflux esophagitis and esophageal spasm may present with or without a history of previous dyspepsia. In the absence of an ECG diagnostic of ischemia, it is worthwhile offering a liquid antacid, but the diagnosis is often retrospective and follows exclusion of ischemic heart disease. Many patients are admitted to a coronary care unit until lack of ECG, exercise testing, or enzyme evidence of ischemic heart disease allows discharge for further gastrointestinal investigation or a trial of a gastric acid secretion inhibitor such as omeprazole.

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