- Standard treadmill exercise testing for diagnosis and risk stratification is suitable for patients with a normal resting electrocardiogram (ECG) and without contraindications to exercise.
- Those with an uninterpretable ECG should undergo either nuclear or echocardiographic imaging in concert with their exercise test.
- Patients in whom exercise is either contraindicated or who have a condition that interferes with exercising to target level are candidates for nuclear or echocardiographic pharmacologic stress testing.
- Patients with suspected coronary heart disease and for whom exercise or pharmacologic testing is contraindicated should be referred to a cardiologist for evaluation.
Most men and women experience symptoms before myocardial infarction (MI).1 Early recognition of these symptoms and prompt treatment are essential for prevention of death and disability related to coronary heart disease (CHD).
Patients with multiple risk factors, chest pain typically suggestive of CHD, or a history of CHD are usually easy to identify and triage. However, many patients do not have obvious risks for CHD but experience occasional symptoms of cardiac ischemia.
Patients can be stratified into low-, intermediate-, and high-risk categories that will help determine appropriate work-up. Those at intermediate risk can be difficult to assess, and may particularly benefit from stress-imaging studies.
The algorithm (Figure 1) is based on current guidelines,2 and indicates how patients with chest pain/symptoms may be identified and treated according to an initial estimate of the probability of obstructive coronary artery disease. The choice of noninvasive diagnostic tests for individuals with stable chest pain and a lower risk for CHD is then outlined.
A 64-year-old, nonsmoking, obese woman with degenerative osteoarthritis of the knees occasionally experiences chest discomfort that lasts for a few minutes, sometimes radiating to her back. The discomfort, which started 4 weeks ago, occasionally becomes worse after a brief walk, but is not usually related to exertion, or associated with nausea or diaphoresis. She sometimes becomes short of breath climbing stairs.
Physical examination: In no acute distress; body-mass index 31.2, waist circumference 42 inches, heart rate 70 beats/min, blood pressure 142/88 mm Hg, cardiovascular examination unremarkable.
Laboratory evaluation: resting electrocardiogram (ECG)—sinus rhythm otherwise normal; creatinine 1.2 mg/dL; fasting glucose 122 mg/dL; glycosylated hemoglobin 6.4%. Lipids: total cholesterol 232 mg/dL; triglycerides 230 mg/dL; high-density lipoprotein (HDL) cholesterol 28 mg/dL; low-density lipoprotein (LDL) cholesterol 158 mg/dL.
A 58-year-old, nonsmoking, otherwise healthy man experiences tightness in the chest, usually at night. The pain began 4 to 8 weeks ago; it lasts as long as 1 to 2 hours but is “very mild.” It does not radiate to the arm or jaw and is unrelated to exertion. There is no diaphoresis or nausea. He sometimes feels a bit winded, which “might be due to anxiety.”
Physical examination: slightly overweight man in no acute distress; body-mass index 27.0, waist circumference 36 inches, heart rate 74 beats/min, blood pressure 138/88 mm Hg, cardiovascular examination unremarkable.
Laboratory evaluation: ECG— sinus rhythm, otherwise normal; creatinine 1.0 mg/dL; fasting glucose 98 mg/dL. Lipids: total cholesterol 215 mg/dL; triglycerides 150 mg/dL; HDL 40 mg/dL; LDL 145 mg/dL.
Standard diagnostic techniques include history, physical examination, laboratory testing as indicated, resting ECG, and assessment of risk factors for CHD.
Evaluation of chest pain
A careful history and physical examination can often quickly exclude many noncardiac causes of chest discomfort or pain. Table 1 contrasts the characteristics of atypical (noncardiac) symptoms with those of typical (cardiac) symptoms. Its quality, location, and the factors that relieve or provoke it, duration, and any associated symptoms should be evaluated. If high-risk or unstable signs or symptoms are present that suggest acute coronary syndrome (unstable angina or MI), evaluation in the emergency department should be performed.
Patients exhibiting stable or atypical (noncardiac) symptoms with some, but not all, of the features of angina described above have a lower probability of coronary artery disease, and should be considered for diagnostic evaluation under the guidance of the primary care physician.3
Characteristics of atypical (noncardiac) vs typical cardiac symptoms
|Quality||Sharp, stabbing, positional||Squeezing, ache, pressure, fullness, burning, heavy, suffocating, “discomfort”|
|Location||Highly localized, below the epigastrium, above the mandible||Diffuse area—substernal, chest, jaw, back, arms|
|Provoked by||“Nothing,” body movement, cough, deep inspiration, chest palpation||Exertion, emotional stress, cold air|
|Relieved by||“Nothing,” position change, analgesics, heat, antacids||Rest; nitroglycerin|
|Duration||“Seconds” (fleeting), or hours, days||30 seconds to 5 minutes|
|Associated symptoms||Reflux/heartburn||Dyspnea, diaphoresis, nausea, fatigue|
In women aged <55 years, noncardiac chest pain is common, but since the prevalence of CHD is increasing among younger women, their symptoms should not be dismissed as “noncardiac” without full evaluation.
Women are also more likely than men to report dyspnea or pain in the jaw or back instead of, or in addition to, chest symptoms. Further, since women are often older and less active when they develop CHD, they may not exhibit typical exertional symptoms. Diagnosis in women is also hampered by lower accuracy of standard stress ECG testing compared with men. False-positive and false-negative tests may occur more frequently in women due to hormonal effects on the ECG, and more frequent comorbidities that limit maximal exercise capacity.