Angina Pectoris: Essentials of Diagnosis

Essentials of Diagnosis

• Precordial chest pain, usually precipitated by stress or exertion, relieved rapidly by rest or nitrates.
  
• Electrocardiographic or scintigraphic evidence of ischemia during pain or stress testing.
  
• Angiographic demonstration of significant obstruction of major coronary vessels.

General Considerations
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). Although treatment is often not very successful in relieving symptoms, the prognosis of syndrome X is good.

Clinical Findings
A. History
The diagnosis of angina pectoris depends principally upon the history, which should specifically include the following information.

1. Circumstances that precipitate and relieve angina - Angina occurs most commonly during activity and is relieved by resting. Exertion that involves straining the thoracic or upper extremity muscles (eg, lifting or walking rapidly uphill) precipitates attacks most consistently. Patients prefer to remain upright rather than lie down. 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. It is usually less after meals, during excitement, or on exposure to cold. The threshold for angina 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.