Angina: Encyclopedia II - Angina - Unstable angina

Angina - Unstable angina

Physicians distinguish between stable angina, which occurs during exercise or stress, and is relieved with a nitrate spray or tablet (e.g., amyl nitrite), and unstable angina, which occurs at rest, or is unrelieved by the usual medication. A patient with angina that is increasing in frequency or severity is also said to have unstable angina.

Unstable angina is very predictive of a heart attack, and requires immediate medical attention. As it is only one of the many potential causes of chest pain, the patient usually has a number of tests in the emergency department, such as a chest X-ray, blood tests (including myocardial markers such as troponin I or T, and a D-dimer if a pulmonary embolism is suspected) and telemetry (monitoring of the heart rhythm).

If the ECG does not show the changes (ST elevation) typical of myocardial infarction (heart attack), the patient may still have suffered a "non-ST elevation MI" (NSTEMI). The accepted management of unstable angina and acute coronary syndrome is therefore empirical treatment with aspirin, heparin (usually a low molecular weight heparin such as enoxaparin), clopidogrel, and intravenous glyceryl trinitrate if the pain persists. A blood test is generally performed for cardiac troponins twelve hours after onset of the pain. If this is positive, coronary angiography is typically performed on an urgent basis, as this is highly predictive of a heart attack in the near-future. If the troponin is negative, a treatmill exercise test or a thallium scintigram may be requested.

Adapted from the Wikipedia article "Unstable angina", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki