Approach to the Patient with Chest Pain

Myocardial Ischemia or Infarction

The most common serious cause of acute chest discomfort is myocardial ischemia or infarction (see Chapter 37, Chapter 38, Chapter 39 ), which occurs when the supply of myocardial oxygen is inadequate for the demand. MI usually occurs in the setting of coronary atherosclerosis, but it may also reflect dynamic components of coronary vascular resistance. Coronary spasm can occur in normal coronary arteries or, in patients with coronary disease surrounding atherosclerotic plaques, and in smaller coronary arteries (see Chapter 36 ). Other less common causes of impaired coronary blood flow include syndromes that compromise the orifices or lumina of the coronary arteries, such as coronary arteritis, proximal aortitis, spontaneous coronary dissection, proximal aortic dissection, coronary emboli from infectious or noninfectious endocarditis or thrombus in the left atrium or left ventricle, myocardial bridge, or a congenital abnormality of the coronary arteries (see Chapter 82 ).

The classic manifestation of ischemia is angina, which is usually described as a heavy chest pressure or squeezing, a burning feeling, or difficulty breathing. The discomfort often radiates to the left shoulder, neck, or arm. It typically builds in intensity over a period of a few minutes. The pain may begin with exercise or psychological stress, but ACS most commonly occurs without obvious precipitating factors.

Atypical descriptions of chest pain reduce the likelihood of myocardial ischemia or injury. The American College of Cardiology (ACC) and American Heart Association (AHA) guidelines list the following as pain descriptions uncharacteristic of myocardial ischemia :

• • Pleuritic pain (i.e., sharp or knifelike pain brought on by respiratory movements or coughing)

  • Primary or sole location of the discomfort in the middle or lower abdominal region

  • Pain that may be localized by the tip of one finger, particularly over the left ventricular apex

  • Pain reproduced with movement or palpation of the chest wall or arms

  • Constant pain that persists for many hours

  • Very brief episodes of pain that last a few seconds or less

  • Pain that radiates into the lower extremities

Nevertheless, data from large populations of patients with acute chest pain indicate that ACS occurs in those with atypical symptoms at sufficient frequency that no single factor suffices to exclude the diagnosis of acute ischemic heart disease. Clinicians should be mindful of “angina equivalents” such as jaw or shoulder pain in the absence of chest pain or dyspnea, nausea or vomiting, and diaphoresis. In particular, women, older persons, and individuals with diabetes may experience atypical symptoms of myocardial ischemia or infarction (see Chapter 91 ). Data from the National Registry of Myocardial Infarction demonstrate that among patients hospitalized with MI, women—particularly young women—less likely manifest chest pain than men.

Pericardial Disease

The visceral surface of the pericardium is insensitive to pain, as is most of the parietal surface. Therefore, noninfectious causes of pericarditis (e.g., uremia; see Chapter 86 ) usually cause little or no pain. In contrast, infectious pericarditis almost always involves the surrounding pleura, so patients typically experience pleuritic pain with breathing, coughing, and changes in position. Swallowing may induce the pain because of the proximity of the esophagus to the posterior portion of the heart. Because the central diaphragm receives its sensory supply from the phrenic nerve, which in turn arises from the third to fifth cervical segments of the spinal cord, pain from infectious pericarditis is frequently felt in the shoulders and neck. Involvement of the diaphragm more laterally can lead to symptoms in the upper part of the abdomen and back, and thus create confusion with pancreatitis or cholecystitis. Pericarditis occasionally causes a steady, crushing substernal pain resembling that of acute MI.

Vascular Disease

Acute aortic dissection (see Chapter 42 ) usually causes a sudden onset of excruciating ripping pain, the location of which reflects the site and progression of the dissection. Ascending aortic dissection manifests as pain in the midline of the anterior aspect of the chest, and posterior descending aortic dissection causes pain in the back of the chest. Aortic dissections are rare, with an estimated annual incidence of 3 per 100,000, and usually occur in the presence of risk factors, including Marfan and Ehlers-Danlos syndromes, bicuspid aortic valve, pregnancy (for proximal dissections), and hypertension (for distal dissections).

Pulmonary emboli (see Chapter 87 ) often cause a sudden onset of dyspnea and pleuritic chest pain, although they may be asymptomatic. ^, Massive pulmonary emboli tend to cause severe and persistent substernal pain, likely due to distention of the pulmonary artery. Emboli that lead to pulmonary infarction can cause lateral pleuritic chest pain. Hemodynamically significant pulmonary emboli may cause hypotension, syncope, and signs of right-sided heart failure. Pulmonary hypertension (see Chapter 88 ) can result in chest pain similar to that of angina pectoris, presumably because of right-heart hypertrophy and ischemia.

Pulmonary Conditions

Pulmonary conditions that cause chest pain generally produce dyspnea and pleuritic symptoms, the location of which reflects the site of pulmonary disease. Tracheobronchitis tends to be associated with a burning midline pain, whereas pneumonia can cause pain over the involved lung. The pain in pneumothorax begins suddenly and is usually associated with dyspnea. Primary pneumothorax typically occurs in tall, thin young men; secondary pneumothorax occurs in the setting of pulmonary disease such as chronic obstructive pulmonary disease, asthma, or cystic fibrosis. Tension pneumothorax can be a life-threatening condition. Asthma exacerbations can be accompanied by chest discomfort, typically characterized as tightness.

Gastrointestinal Conditions

Irritation of the esophagus by acid reflux can produce a burning discomfort that may be exacerbated by intake of alcohol, aspirin, and some foods. Symptoms are often worsened by a recumbent position and are relieved by sitting upright and with acid-reducing therapies. Esophageal spasm can cause a squeezing chest discomfort similar to that of angina. Mallory-Weiss tears of the esophagus can occur in patients who have had prolonged vomiting episodes. Severe vomiting can also result in esophageal rupture (Boerhaave syndrome) with mediastinitis. Chest pain caused by peptic ulcer disease usually occurs 60 to 90 minutes after meals and typically responds rapidly to acid-reducing therapies. This pain is generally epigastric in location but can radiate to the chest and shoulders. Cholecystitis causes a wide range of pain syndromes and generally causes right upper quadrant abdominal pain, but chest and back pain is not unusual. The pain is frequently described as aching or colicky. Pancreatitis typically causes an intense, aching epigastric pain that may radiate to the back, with limited relief through acid-reducing therapies.

Musculoskeletal and Other Causes

Chest pain can arise from musculoskeletal disorders involving the chest wall (such as costochondritis), conditions affecting the nerves of the chest wall (such as cervical disc disease), by Herpes zoster, or following heavy exercise. Chest pain secondary to musculoskeletal causes is often elicited by direct pressure over the affected area or by movement of the patient’s neck. The pain itself can be fleeting, or it can be a dull ache that lasts for hours. Panic syndrome is a major cause of chest discomfort in ED patients. The symptoms typically include chest tightness, often accompanied by shortness of breath and a sense of anxiety, and generally last 30 minutes or longer.

Clinical Evaluation

When evaluating patients with acute chest pain, clinicians must address a series of issues related to prognosis and immediate management. ^, Even before arriving at a definite diagnosis, high-priority questions include the following:

• • Clinical stability: Does the patient need immediate treatment for actual or impending circulatory collapse or respiratory insufficiency?

  • Immediate prognosis: If the patient is currently clinically stable, what is the risk that a life-threatening condition such as ACS, PE, or aortic dissection exists?

  • Safety of triage options: If the risk for a life-threatening condition is low, is it safe to discharge the patient for outpatient management, or should further testing or observation to guide management be undertaken?

Initial Assessment

Evaluation of a patient with acute chest pain can begin before the physician sees the patient, and thus effectiveness may depend on the actions of the office staff and other nonphysician personnel. Guidelines from the ACC/AHA and European Society of Cardiology (ESC) ^, emphasize that patients with symptoms consistent with ACS should not be evaluated solely on the phone but should be referred to facilities to be evaluated by a physician and undergo a 12-lead electrocardiogram (ECG). These guidelines also recommend strong consideration of immediate referral to an ED or a specialized chest pain unit for patients with suspected ACS who experience chest discomfort at rest for longer than 20 minutes, hemodynamic instability, or recent syncope or near-syncope. Transport as a passenger in a private vehicle is considered an acceptable alternative to an emergency vehicle only if the wait would lead to a delay longer than 20 to 30 minutes.

Patients with the following chief complaints should undergo immediate assessment by triage nurses and be referred for further evaluation:

• • Chest pain, pressure, tightness, or heaviness; pain that radiates to the neck, jaw, shoulders, back, or one or both arms

  • Indigestion or heartburn; nausea and/or vomiting associated with chest discomfort

  • Persistent shortness of breath

  • Weakness, dizziness, lightheadedness, or loss of consciousness

For such patients, initial assessment involves taking a history, performing a physical examination, obtaining an ECG and chest radiograph, and measuring biomarkers of myocardial injury. Recent data suggest important sex-based disparities in the assessment and outcome of chest pain evaluations in emergency rooms. In one analysis with over 54,000 patients, after adjusting for baseline differences, women were 18% less likely to be reviewed within 10 minutes and 16% less likely to be evaluated within an hour presentation. Such observations underscore the need for more systematic and unbiased approaches to initially evaluate chest pain.