Enhanced recognition of ischemia by three variable analysis of the exercise stress test☆,☆☆
Introduction
For many years ECG ST-segment depression has been the primary variable used to diagnose myocardial ischemia during the exercise stress test (EST). This practice has continued despite several studies that demonstrated the superiority of using multiple indicators to improve the diagnostic accuracy as early as 1977.1 Although using several variables demonstrated that the probability of identifying single vessel disease was as high as 66%, and 81% in 3 vessel disease, it was never adopted.2
Because competing diagnostic methods, such as cardiac computed tomography (CT) scans and myocardial perfusion imaging (MPI), with greater cost have become popular, we present a recent study where multiple variables are used to improve the diagnostic accuracy of detecting myocardial ischemia during the EST. This study incorporates recent findings that elaborate on unconventional indicators of ischemia that have proven to be superior to exercise-induced ST-segment deviation alone in determining if myocardial ischemia with early ventricular dysfunction is present. Current practice and guidelines continue to focus on exercise-induced ST deviations and exercise-induced angina pectoris. This study evaluates the efficacy of routinely combining pathophysiological variables to optimize the early detection of myocardial ischemia during the EST.
Section snippets
Materials and methods
We enrolled cases of consecutive patients who underwent an EST with MPI between January 2005 and June 2009 at the Memorial Heart and Vascular Institute of Long Beach Memorial Medical Center. Patients were referred by physicians because of suspected coronary artery disease. Patients must have completed an EST with resting and stress single-photon emission computed tomography (SPECT) MPI studies. Excluded from enrollment were patients with atrial fibrillation, artificially paced rhythms, less
Results
There were 439 patients enrolled in the study, comprising 255 men and 184 women. Demographic and clinical factors are reported in Table 1. EST data are reported in Table 2. Men were significantly more likely to have ischemic REVERSIBLE DEFECT MPI results (p = 0.011). Patients who reported a history of chest pain or exercise-induced chest pain were not significantly associated with ischemic REVERSIBLE DEFECT MPI results (p = 0.147 and p = 0.096 respectively). Abnormal ST elevation in AVR was
Discussion and conclusions
Our study establishes that the accuracy of the EST is improved by including more than one ECG measurement. For many years ST-segment depression ≥ 1 mm has been the gold standard that has been almost universally accepted. This study clearly established that more than one variable will improve the accuracy of EST, a message that was reported in 1981.6 Over the years, we have reported a number of unconventional ECG indicators of ischemia, although most of them had decreased sensitivities, many of
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Cited by (0)
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This study is funded by the Memorial Medical Center Foundation, Long Beach, CA.
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The authors have no affiliations with industry or other conflicts of interest to disclose.