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[Myocardial ischemia with negative stress electrocardiography: evaluation by stress RI studies]
T Yada1, Y Futagami, M Yamamuro
1First Department of Internal Medicine, Mie University, Tsu.
Insights
Radionuclide imaging (RI) tests are more sensitive than stress electrocardiography (ECG) for detecting stress-induced ischemia in patients with old myocardial infarction or effort angina, even with negative ECG results.
Area of Science:
- Cardiology
- Nuclear Medicine
- Diagnostic Imaging
Background:
- Stress electrocardiography (ECG) has limitations in detecting myocardial ischemia, particularly in patients with old myocardial infarction (OMI) and effort angina (EA).
- Re-evaluation using radionuclide imaging (RI) studies, including 201Tl single photon emission computed tomography (SPECT) and 99mTc-RBCs radionuclide ventriculography (RNV), was performed on patients with negative stress ECG results.
Observation:
- Among patients with negative stress ECG, a significant proportion showed positive SPECT results (54% of OMI, 73% of EA).
- Negative stress ECG did not exclude abnormal findings in ejection fraction (delta EF < 5%) or regional wall motion (41% of OMI, 28% of EA).
- No correlation was found between negative ECG and the extent of coronary artery disease or infarction in OMI patients.
Findings:
- RI testing, including SPECT and RNV, demonstrated higher sensitivity for detecting stress-induced ischemia compared to stress ECG.
- Radionuclide imaging identified significant ischemia and abnormal cardiac function in a substantial number of patients with initially negative stress ECGs.
Implications:
- RI testing should be considered for patients with suspected ischemia who have non-diagnostic stress ECG results.
- These findings highlight the complementary role of nuclear cardiology techniques in the comprehensive assessment of ischemic heart disease.
- Improved diagnostic accuracy through RI testing can potentially lead to more timely and appropriate patient management.
Abstract:
Patients with negative stress electrocardiography (ECG) (no ST segment depression) were re-evaluated by means of stress RI studies including 201T1 single photon emission computed tomography (SPECT) and 99mTc-RBCs radionuclide ventriculography (RNV). Four hundred seven patients, including 303 with old myocardial infarction (OMI; SPECT: 188, RNV: 115) and 104 with effort angina (EA; SPECT: 58, RNV: 46), all of whom underwent left ventriculography and coronary arteriography, were re-evaluated by symptom-limited graded bicycle ergometer exercise RI testing. The results were as follows: 1. Among those with negative stress ECG (53% of OMI and 31% of EA), 54% and 73% of OMI and EA, respectively, had positive SPECT. 2. Among those with negative stress ECG (56% of OMI and 39% of EA), 70% and 39% of OMI and EA, respectively, had positive delta EF (poor increase in ejection fraction: delta EF less than 5%) and, 41% and 28% of OMI and EA had deteriorated regional wall motion. 3. Those with OMI and negative ECG showed no correlations with the numbers of diseased vessels, infarcted sites, or ischemic areas. In conclusion, RI testing appears to be a significantly more sensitive means of detecting stress-induced ischemia, compared to stress ECG.