Inappropriate Stress Testing in an Asymptomatic Patient with Sinus Bradycardia
Richard S. Fernandes Almeida
D. A. Neville Mascarenhas
A 71-year-old asymptomatic male was referred to a cardiologist for a treadmill stress test. The patient’s primary care physician sent him for this test after observing that patient had sinus bradycardia (heart rate of 44beats per minute). Results of the test revealed a ST segment depression at peak exercise. In response to these abnormal results, the patient was referred to us for an exercise gated sestamibi SPECT (single photon emission computed tomography) study. This revealed normal left ventricular systolic function and no evidence of ischemia. Stress testing is not indicated for asymptomatic arrhythmias. Therefore, we believe that the initial treadmill stress testing in this case was unnecessary and led to further superfluous testing.
A 71-year-old Caucasian male, with a history of transient ischemic attacks (TIA), hypertension, bradycardia, gout, and hypercholesterolemia was referred to an outpatient cardiology office for a stress test. The test had been obtained by his primary care physician because the patient was found to be bradycardic (Figure 1).
The report of the test showed down-sloping ST segment depression (2 mV) in inferior and lateral leads at 82% of maximum age-predicted heart rate achieved and a maximum post-stress blood pressure of 243/80 mmHg. The test had been stopped due to the patient’s shortness of breath, but there was no chest discomfort. In view of his abnormal stress test, he was referred to us for a SPECT Sestamibi exercise gated study. At peak exercise, the patient developed a 2 mm ST depression which persisted for 2 minutes’ post-exercise (Figure 2).
A nuclear stress test (sestamibi SPECT exercise gated study) was obtained which showed normal pre- and post- stress sestamibi uptake, normal systolic function with estimated ejection fraction of 60% (Figure 3).
Indications for treadmill stress testing include stable anginal symptoms (in patients with intermediate to high pretest probability of coronary heart disease), monitoring of known coronary artery disease, newly diagnosed heart failure or cardiomyopathy, and screening prior to non-cardiac surgery or competitive sports. It is also indicated for patients with symptoms that suggest exercise-induced arrhythmias (e.g., syncope).
The patient in this report underwent a treadmill stress test for asymptomatic bradycardia. However, as per the current guidelines from the American College of Cardiology (ACC) and American Heart Association (AHA), there are no indications for performing stress tests in this population. Stress testing for screening of asymptomatic low-risk patients is generally not indicated or appropriate. Rare exceptions are patients with multiple risk factors and those in high-risk occupations (e.g., airline pilots). A recent study estimates that in the United States, 30% of imaging stress tests and 14% of non-imaging tests are ordered without appropriate indications. The estimated costs from this unnecessary stress testing amounts to $494 million annually. Additionally, patients are exposed to up to 10.2 million mSv per year of radiation from these tests, which could lead to 491 extra cases of cancer per year. It is important to obtain testing only when it is necessary and if it will influence patient management, to avoid the waste of resources and time and to prevent the potential adverse health effects of excessive testing.
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