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The "false negative" treadmill exercise test and left ventricular dysfunction
Insights
Exercise stress tests can miss coronary artery disease, especially when left ventricular dysfunction is present. These false negative results indicate underlying heart abnormalities despite a normal exercise response.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Exercise Physiology
Background:
- Graded exercise testing (GXT) is a common tool for diagnosing coronary artery disease (CAD).
- However, false negative responses can lead to underdiagnosis and delayed treatment.
- Understanding factors contributing to false negatives is crucial for improving diagnostic accuracy.
Purpose of the Study:
- To evaluate the sensitivity, specificity, and false negative rates of GXT in symptomatic patients.
- To identify patient characteristics and underlying cardiac conditions associated with false negative GXT results.
- To explore the relationship between false negative responses and left ventricular function.
Main Methods:
- Retrospective analysis of 115 symptomatic patients undergoing GXT, coronary angiography, and left ventriculography.
- Calculation of sensitivity, specificity, and false negative rates for GXT.
- Comparison of ventriculographic and hemodynamic data between true positive and false negative groups.
Main Results:
- GXT demonstrated a sensitivity of 79%, specificity of 81%, and a false negative rate of 21%.
- False negative responses were not significantly different across varying degrees of coronary artery disease (single, double, or triple vessel disease).
- Patients with false negative GXT showed significant ventriculographic and hemodynamic abnormalities, including impaired ventricular motion and higher rates of occluded vessels supplying abnormal segments.
Conclusions:
- Left ventricular dysfunction is a significant factor contributing to false negative exercise test responses.
- Abnormal myocardial segments supplied by occluded vessels may be related to the absence of an "ischemic response" on GXT.
- GXT accuracy can be limited in patients with underlying left ventricular abnormalities.
Abstract:
One hundred and fifteen consecutive symptomatic patients undergoing graded exercise testing, selective coronary angiography and left ventriculography were retrospectively evaluated. The sensitivity, specificity, and false negative response rates of the exercise tests were 79%, 81%, and 21%, respectively. Although the magnitude of a positive ST-segment response was related to more extensive vascular disease, the frequency of false negative responses was nearly identical in patients with single, double, or triple vessel disease (22%, 21%, 19%). Analysis of the false negative group demonstrated significant ventriculographic and hemodynamic abnormalities when compared to the true positive responders. Five out of six patients with the most serious motion disorders in the study fell into the false negative group. There were no significant differences in the extent, distribution and severity of vascular involvement, or in the development of collateral circulation in the two groups. However, occluded vessels supplied abnormal ventricular segments more frequently in the false negative group (88% vs 38%); the absence of an "ischemic response" and the presence of segments of abnormal myocardium may be related. Left ventricular dysfunction appears to be an important reason for a false negative response to exercise.