Cardiovascular Division (Clinical) Elliott Antman, MD Donald S. Baim, MD Joshua Beckman, MD Charles M. Blatt, MD Eugene Braunwald, MD Christopher Cannon, MD Ming Hui Chen, MD Michael Chin, MD, PhD Mark Creager, MD Victor Dzau, MD Elazer Edelman, MD, PhD Andrew Eisenhauer, MD Laurence Epstein, MD James Fang, MD Mark Feinberg, MD Jonas Galper, MD, PhD Peter Ganz, MD J. Michael Gaziano, MD Marie Gerhard-Hermen, MD Robert Giugliano, MD Michael Givertz, MD Samuel Z. Goldhaber, MD Thomas B. Graboys, MD Howard Hartley, MD Carolyn Ho, MD Mukesh Jain, MD John Jarcho, MD Paula Johnson, MD Ralph Kelly, MD Scott Kinlay, MD Jamil Kirdar, MD James Kirshenbaum, MD Gideon Koren, MD Richard Kuntz, MD Raymond Kwong, MD Michael J. Landzberg, MD Jennifer Larsen, MD Dara Lee, MD Richard Lee, MD James Liao, MD Peter Libby, MD (Division Chief) Leonard Lilly, MD Bernard Lown, MD William Maisel, MD Thomas Michel, MD, PhD David Morrow, MD Karen Moulton, MD Gilbert Mudge, MD Patrick O’Gara, MD Marc A. Pfeffer, MD, PhD (Editor) Jorge Plutzky, MD Jeffrey Popma, MD Shmuel Ravid, MD Frederic Resnic, MD Paul Ridker, MD Thomas Rocco, MD Campbell Rogers, MD Maria Rupnick, MD, PhD Arthur Sasahara, MD Jay Schneider, MD Christine Seidman, MD Andrew Selwyn, MD Daniel Simon, MD Laurence Sloss, MD Regina Sohn, MD Scott Solomon, MD Lynne Stevenson, MD William Stevenson, MD Peter Stone, MD Michael Sweeney, MD Frederick Welt, MD Brigham and Women’s Hospital Fax: (617) 732-5291Website: www.heartdoc.org The editorial content of Cardiology Rounds is determined solely by the Cardiovascular Division of Brigham and Women’s Hospital. This publication is made possible by an educational grant. A Teaching Hospital of HARVARD MEDICAL SCHOOL Although exercise electrocardiography is one of the most commonly performed, non- invasive diagnostic tests in the United States, it has fallen into relative disfavor in relation to other noninvasive modalities, including nuclear perfusion scintigraphy, PET scanning, and stress echocardiography. 1 Exercise electrocardiography, as well as noninvasive imaging studies, are commonly thought of as a means of diagnosing coronary artery disease. 2 That is, the clinician caring for a patient with known or suspected disease, is interested in knowing whether or not there is a coronary artery stenosis present that is severe enough to cause measurable myocardial ischemia. According to recent American College of Cardiology and American Heart Association guidelines, the exercise electrocardiogram has two accepted roles in clinical care: 2,3 • for diagnostic evaluation • for assessment of long-term risk in patients thought to be at intermediate or high like- lihood of having significant coronary disease. 3 Although much literature has been written about the value of noninvasive testing for predicting risk, most clinicians still think of the exercise test as primarily a diagnostic tool. Furthermore, the main measure that attracts attention is the behavior of the ST segment during and after exercise. The first part of this review, demonstrates how the diagnostic model of employing exercise testing is fundamentally flawed and that the real value of the test lies in its strong ability to predict risk, particularly when measures other than the ST segment are considered. In Part 2 of this topic, in the next issue of Cardiology Rounds, the discussion will focus on the value of attenuated heart rate recovery as an independent predictor of increased mortality risk. The diagnostic model There are two fundamental problems with the diagnostic model of exercise testing, and in fact, of noninvasive testing in general. First, nearly all studies pertaining to the accuracy of non- invasive testing suffer from verification bias. 4-7 Second, the currently accepted gold standard – namely coronary angiography – is itself an inherently limited test. 8 Nearly all literature regarding the accuracy of noninvasive testing involves cohorts of patients in whom noninvasive testing and coronary angiography were both performed as part of routine clinical care. While such cohorts are attractive and relatively easy to study, analysis of them suffers from a serious problem. The theory underlying evaluation of test accuracy assumes that Exercise Testing Part 1: Looking Beyond the ST Segment BY MICHAEL S. LAUER, MD, FACC, FAHA May 2002 Volume 6, Issue 5 ™ Available on the Internet www.cardiologyrounds.org Available on the Internet www.cardiologyrounds.org