Angina pectoris (AP) represents the clinical syndrome occurring when myocardial oxygen demand exceeds supply. The term is derived from Latin; the literal meaning is “the choking of the chest;” angere, meaning “to choke” and pectus, meaning “chest.” The first English-written account of recurrent angina pectoris was by English nobleman Edward Hyde, Earl of Clarendon. He described his father as having, with exertion, “a pain in the left arm…so much that the torment made him pale”.  The first description of angina as a medical disorder came from William Heberden. Heberden, a prodigious physician, made many noteworthy contributions to medicine during his career. He presented his observations on “dolor pectoris” to the Royal College of Physicians in 1768. Much of his classic description retains its validity today. 
Angina pectoris has a wide range of clinical expressions. The symptoms most often associated to angina pectoris are substernal chest pressure or tightening, frequently with radiating pain to the arms, shoulders, or jaw. The symptoms may also be associated with shortness of breath, nausea, or diaphoresis. Symptoms stem from inadequate oxygen delivery to myocardial tissue. No definitive diagnostic tools that capture all patients with angina pectoris exist. This, combined with its varied clinical expression, makes angina pectoris a distinct clinical challenge to the emergency physician. The disease state can manifest itself in a variety of forms, including the following:
- Stable angina pectoris is classified as a reproducible pattern of anginal symptoms that occur during states of increased exertion.
- Unstable angina pectoris (UA) manifests either as an increasing frequency of symptoms or as symptoms occurring at rest.
- Prinzmetal angina or variant angina occurs as a result of transient coronary artery spasms. These spasms can occur either at rest or with exertion. Unlike stable or unstable angina, no pathological plaque or deposition is present within the coronary arteries that elicits the presentation. On angiography, the coronary arteries are normal in appearance with spasm on angiography.
- Cardiac syndrome X occurs when a patient has all of the symptoms of angina pectoris without coronary artery disease or spasm.
As previously stated, there is no standard presentation of angina. One must be vigilant for anginal equivalents, such as breathlessness or diaphoresis, in all subgroups of patients.
No amount of testing can routinely be performed in the emergency department setting to definitively rule out angina as the cause of a patient’s chest pain or suspected anginal equivalent.
Reproducible chest wall pain is found in roughly 10% of all cases of AMI. 
Other conditions to be considered in the differential diagnosis of patients with suspected angina include the following:
- Abdominal aortic aneurysm
- Anxiety disorders
- Aortic dissection
- Boerhaave syndrome
- Biliary colic
- Cardiomyopathy, hypertrophic
- Coronary artery atherosclerosis
- Coronary artery vasospasm
- Gastric ulcers
- Gastritis, acute
- Gastroesophageal reflux disease
- Hiatal hernia
- Hypercholesterolemia, familial
- Hypercholesterolemia, polygenic
- Hyperventilation syndrome
- Isolated coronary artery anomalies
- Kawasaki disease
- Panic disorder
- Peptic ulcer disease
- Pericardial effusion
- Pericarditis, acute
- Polyarteritis nodosa
- Pott disease (tuberculous spondylitis)
- Pulmonary hypertension, primary
- Pulmonary hypertension, secondary
- Takayasu arteritis
- Tietze syndrome
- Varicella-zoster virus anemia
- Esophageal spasm
- Pneumonia with pleural involvement
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The laboratory workup of patients with angina includes the following tests:
- CBC (anemia, leukocytosis may suggest an alternative diagnosis)
- BUN and creatinine level, if intravenous contrast is anticipated
- Electrolyte levels are of virtually no value unless the patient is on a diuretic and concern for an abnormality exists.
- Cardiac enzyme levels, if positive may suggest non–ST-segment elevation myocardial infarction (NSTEMI); negative results do not rule out ischemia
- Coagulation studies, if anticoagulation or antiplatelets are anticipated
- Type and screen, if surgery or transfusions are considered
Chest radiography is used to rule out an alternative diagnosis or contributing factors (eg, pneumothorax [PTX], pneumonia [PNA], congestive heart failure); it is also used to evaluate the aorta prior to anticoagulant administration.
CT of the chest may be considered for evaluation of aortic or pulmonary disease; if evaluating the aorta, include the abdominal aorta. Of note, the forthcoming “triple rule out CT scan” exposes the patient to an exorbitantly high dose of radiation and should only be used in certain circumstances.
Limited CT coronary scans may help to reduce the posttest probability of coronary artery disease while utilizing potentially less radiation exposure than the “triple rule out scan.” Coronary artery calcification suggests the presence of an atherosclerotic plaque. Calcium scores are determined by the density of calcium and the total area. Higher calcium scores may suggest a higher risk of current or future adverse cardiac events. Multiple sites are currently conducting trials to see if this modality will benefit patients in the emergency department.
Bamberg et al found that, in patients with acute chest pain and an inconclusive initial evaluation (nondiagnostic electrocardiographic findings, negative cardiac biomarkers), age and gender can serve as simple criteria to select patients who would derive the greatest diagnostic benefit from coronary computed tomographic angiography (CTA).  In an observational cohort study in 368 low-risk patients, positive findings on 64-slice coronary CTA led to restratification to high risk, and negative findings led to restratification to very low risk, in men younger than 55 years and women younger than 65 years. In contrast, in women older than 65 years and men older than 55 years, a negative result on CTA did not result in restratification to a low-risk category.
Nuclear imaging should include V/Q (PE evaluation) and resting Sestamibi (In the appropriate clinical setting, a normal study in a patient with ongoing chest pain may rule out myocardial ischemia.  ).
ECG results may be normal or show signs of ischemia. Main use is to establish a baseline and R/O acute ST-segment elevation myocardial infarction (STEMI).
Intraluminal coronary artery sonography (ICAS) is a highly invasive modality that may provide additional information to a patient’s coronary artery anatomy and disease. Coronary atherosclerosis, which does not result in coronary artery narrowing, may be missed by conventional forms of coronary angiography. If clincially suspected, ICAS may be utilized to detect the presence or absence of such lesions. ICAS is not readily available; as such, it is highly unlikely that ICAS will be utilized from the emergency department in the foreseeable future.
The use of stress cardiac MRI in an observation unit may be a cost-saving alternative to inpatient management for emergency department patients with chest pain. In a randomized study in 110 patients, Miller et al reported that an observation unit strategy with stress cardiac MRI reduced median hospitalization cost by approximately $588, with no cases of missed acute coronary syndrome.
Emergency Department Care
In the ED, the patient who complains of chest discomfort needs to be immediately assessed for AMI as well as other high-risk diagnoses (eg, aortic dissection, pulmonary embolism). Vital in this assessment is an early ECG and a rapid history and physical examination. Should this initial encounter not reveal a definitive diagnosis, then a more focused history and physical examination needs to be performed. Serial ECGs, especially in the setting of changing symptoms, is imperative. Labeling the ECGs with the patient’s level of pain is often useful. A consecutive series of ECGs taken when a patient is having “10/10” pain, “3/10” pain, and “0/10” pain may yield valuable information that would not be readily apparent with an isolated cardiogram. Continuous telemetry monitoring is recommended for higher-risk patients. 
The patient who presents with chest pain is presumed to have underlying clinically significant cardiac pathology (ie, unstable angina or NSTEMI).
The initial treatment consists of administration of oxygen, aspirin, nitroglycerin, morphine, and a beta-blocker. Given an altered, yet nondiagnostic ECG and no contraindications, further treatment with heparin (low-molecular weight or unfractionated), clopidogrel, or other antiplatelet agents may be initiated. Most often, an additional abnormal marker (eg, an elevated serum troponin, myoglobin, or CPK level) will be verified prior to antiplatelet therapy.
For persistent symptoms unresponsive to initial therapy, glycoprotein inhibitors can be considered. These appear to demonstrate an additional benefit in the patient population who will be undergoing cardiac catheterization (PCI).  Persistent pain, in spite of this treatment, suggests either AMI or an alternative diagnosis. In the case of AMI, angioplasty or thrombolytics should be administered if available and not contraindicated. The American College of Cardiology offers an excellent evidenced-based online treatment resource
Atypical presentations of angina, unfortunately, are often diagnosed retrospectively. This subset of patients is identified either when their condition progresses to STEMI or through elevated serum marker levels or cardiac dysrhythmia (often ventricular tachycardia or fibrillation). It cannot be understated that the variance of expression of angina pectoris makes it imperative that the clinician have a high level of suspicion for the disease. Little value exists in relying on a constancy of expression or on ECG, history, or physical examination alone for making the diagnosis. Angina pectoris should be considered as well as an extensive differential diagnosis, in just about any patient who presents to the ED with chest pain with or without other nonspecific complaints.
Syndrome X and Prinzmetal angina are not diagnosed in the ED, but the patient’s medical records or primary care physician may be helpful in recognizing these disorders.