A 52-year-old woman is evaluated for a 6-week history of chest pressure. The symptom occurs when she walks up an incline on her daily 2-mile walk and is relieved with rest. She also had chest pressure during a stressful meeting at work last week. She reports no associated symptoms. Medical history is significant for hypertension and hyperlipidemia. Medications are hydrochlorothiazide, lisinopril, and atorvastatin.
On physical examination, vital signs and the remainder of the examination are normal.
An electrocardiogram is normal.
Which of the following is the most appropriate diagnostic test to perform next?
A. Adenosine single-photon emission CT
B. Coronary artery calcium scoring
C. Exercise electrocardiography
D. Stress echocardiography
MKSAP Answer and Critique
The correct answer is C. Exercise electrocardiography. This content is available to MKSAP 18 subscribers as Question 27 in the Cardiology section. More information about MKSAP is available online.
The most appropriate test to establish a diagnosis of coronary artery disease (CAD) is exercise electrocardiographic (ECG) stress testing. This patient with cardiovascular risk factors (hypertension, hyperlipidemia) is exhibiting typical angina, which has the following characteristics: (1) substernal chest pain or discomfort that (2) is provoked by exertion or emotional stress and (3) is relieved by rest and/or nitroglycerin. Given her age, sex, and symptoms, she has an intermediate pretest probability of CAD (73%) and should undergo stress testing. In patients with a normal baseline ECG and the ability to exercise, exercise ECG is recommended as the initial test of choice. Exercise ECG can identify flow-limiting lesions indicative of CAD and also further risk stratify this patient. The additional prognostic information available with exercise, including functional capacity and heart rate and blood pressure response, can be used in prediction models, such as the Duke Treadmill Score, which uses several factors (development of symptoms, degree of ST-segment depression, and exercise duration) to provide incremental prognostic information for 5-year mortality risk. Heart rate recovery is another powerful predictor; patients with a heart rate drop of less than 12/min in the first minute after cessation of exercise have a higher mortality rate.
There is no indication for stress testing with additional imaging, such as adenosine single-photon emission CT or stress echocardiography, given this patient's normal baseline ECG findings. If the baseline ECG findings were uninterpretable or the exercise ECG stress test was indeterminate, additional testing with imaging would be warranted.
Coronary artery calcium scoring would identify the presence of CAD, but it would not detect a flow-limiting lesion as the cause of this patient's symptoms. Additionally, the absence of calcification during coronary artery calcium scoring does not exclude the presence of noncalcified plaque.
- In patients with an intermediate probability of obstructive coronary artery disease, a normal baseline electrocardiogram, and the ability to exercise, exercise electrocardiography is recommended as the initial test of choice.