Related Experiment Videos
Noninvasive testing in the evaluation of myocardial ischemia: agreement among tests
Insights
This study found weak correlations between common indicators of heart ischemia in patients with coronary heart disease. Exercise test results for angina, ST depression, ejection fraction, and thallium defects showed poor agreement.
Area of Science:
- Cardiology
- Exercise Physiology
- Diagnostic Imaging
Background:
- Coronary heart disease (CHD) diagnosis relies on various exercise-induced indicators.
- Understanding the agreement between these indicators is crucial for accurate patient assessment.
Purpose of the Study:
- To investigate the relationships among four exercise-induced phenomena: angina, ST segment depression, decreased ejection fraction, and thallium perfusion defects.
- To determine the impact of these phenomena on aerobic capacity in patients with documented CHD.
Main Methods:
- 156 men with documented CHD underwent radionuclide ventriculography, thallium scintigraphy, and treadmill testing.
- Measurements included computerized electrocardiography and maximal oxygen uptake.
- Data were analyzed for correlations between the four indicators of ischemia.
Main Results:
- Out of 624 tests, 39% indicated ischemia, with an average of 1.6 abnormal tests per patient.
- The four indicators of ischemia showed poor correlation when treated as continuous variables.
- Correlations did not improve after adjusting for heart rate or excluding patients with prior bypass surgery or myocardial infarction.
- Treadmill performance was significantly impaired by angina but less so by other ischemia indicators.
Conclusions:
- The study concludes that common exercise test responses implying ischemia have weak agreement when applied uniformly to patients with known coronary artery disease.
- This suggests limitations in relying on a single indicator for comprehensive ischemia assessment.
Abstract:
The purpose of this study was to investigate the relations among four exercise-induced phenomena--angina, ST segment depression, decrease in ejection fraction and thallium perfusion defects--and to determine their impact on aerobic capacity. One hundred fifty-six men (mean age 52 +/- 8 years) with documented coronary heart disease were studied with radionuclide ventriculography during supine bicycle exercise, thallium scintigraphy and treadmill testing with computerized electrocardiography and maximal oxygen uptake. Of 624 administered tests, 243 results (39%) were considered to indicate ischemia. The average number of abnormal tests was 1.6 per patient and, when considered as continuous variables, their results correlated poorly. Correlations did not improve when adjusting for heart rate achieved or by eliminating patients with coronary artery bypass surgery or myocardial infarction. Statistical methods of comparing degree of interest agreement yielded surprisingly weak relations among the four tests of ischemia. Treadmill performance was markedly impaired by angina, but much less impaired by other indicators of ischemia. It is concluded that the usual test responses implying ischemia have weak agreement when uniformly applied to patients with known coronary artery disease.