“False-Positive” Stress Tests in Patients with Coronary Microvascular Dysfunction

The false-positive rate of exercise stress electrocardiography testing (EST) can be substantial when EST is validated against angiography for diagnosing obstructive coronary artery disease. However, a new study calls that interpretation into question. Researchers in the U.K. evaluated 102 patients (mean age, 60) who had angina without obstructive coronary artery disease; patients underwent EST, as well as invasive assessment with acetylcholine and adenosine infusion for coronary microvascular dysfunction (CMD), which also can cause ischemia.

Thirty-two patients developed ischemia on EST, all of whom tested positive for CMD. Seventy patients had nonischemic EST results, of whom 46 (66%) received diagnoses of CMD. When the reference standard w…