ESSENTIALS OF DIAGNOSIS
Precordial chest pain, usually precipitated by stress or exertion, relieved rapidly by rest or nitrates.
ECG or scintigraphic evidence of ischemia during pain or stress testing.
Angiographic demonstration of significant obstruction of major coronary vessels.
Angina pectoris is usually due to atherosclerotic heart disease. Coronary vasospasm may occur at the site of a lesion or, less frequently, in apparently normal vessels. Other unusual causes of coronary artery obstruction, such as congenital anomalies, emboli, arteritis, or dissection may cause ischemia or infarction. Angina may also occur in the absence of coronary artery obstruction as a result of severe myocardial hypertrophy, severe aortic stenosis or regurgitation, or in response to increased metabolic demands, as in hyperthyroidism, marked anemia, or paroxysmal tachycardias with rapid ventricular rates. Rarely, angina occurs with angiographically normal coronary arteries and without other identifiable causes. This presentation has been labeled syndrome X and is most likely due to inadequate flow reserve in the resistance vessels (microvasculature). Syndrome X remains difficult to diagnose. Although treatment is often not very successful in relieving symptoms, the prognosis of syndrome X is good.
The diagnosis of angina pectoris principally depends on the history, which should specifically include the following information: circumstances that precipitate and relieve angina, characteristics of the discomfort, location and radiation, duration of attacks, and effect of nitroglycerin.
1. Circumstances that precipitate and relieve angina
Angina occurs most commonly during activity and is relieved by resting. Patients may prefer to remain upright rather than lie down, as increased preload in recumbency increases myocardial work. The amount of activity required to produce angina may be relatively consistent under comparable physical and emotional circumstances or may vary from day to day. The threshold for angina is usually lower after meals, during excitement, or on exposure to cold. It is often lower in the morning or after strong emotion; the latter can provoke attacks in the absence of exertion. In addition, discomfort may occur during sexual activity, at rest, or at night as a result of coronary spasm.
2. Characteristics of the discomfort
Patients often do not refer to angina as “pain” but as a sensation of tightness, squeezing, burning, pressing, choking, aching, bursting, “gas,” indigestion, or an ill-characterized discomfort. It is often characterized by clenching a fist over the mid chest. The distress of angina is rarely sharply localized and is not spasmodic.
3. Location and radiation
The distribution of the distress may vary widely in different patients but is usually the same for each patient unless unstable angina or MI supervenes. In most cases, the discomfort is felt behind or slightly to the left of the mid sternum. When it begins farther to the left ...