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Abnormal thallium stress test and normal coronary angiograms: catheterization and clinical characteristics
1Department of Cardiology, Soroka Medical Center, Beer Sheva, Israel.
Insights
Patients with abnormal thallium stress tests but normal coronary angiograms may have two underlying conditions: coronary flow disturbances or true false positive tests. Further research is needed to differentiate these groups.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Diagnostic Imaging
Background:
- Abnormal thallium stress tests with normal coronary angiograms present a diagnostic challenge.
- Understanding the underlying pathophysiology is crucial for accurate patient management.
Purpose of the Study:
- To investigate potential differences in left ventricular function and patient characteristics between two subgroups of patients exhibiting abnormal thallium stress tests despite normal coronary angiograms.
- To explore whether these subgroups represent distinct clinical entities.
Main Methods:
- Analysis of left ventricular end-diastolic pressure (LVEDP) and left ventricular ejection fraction (LVEF) in 40 patients.
- Categorization into two groups based on LVEDP and LVEF: Group 1 (elevated LVEDP, low-normal LVEF) and Group 2 (normal LVEDP, high-normal LVEF).
- Assessment of thallium segmental abnormalities, sex, age, and risk factors (diabetes mellitus, hypertension, hypercholesterolemia, smoking).
Main Results:
- Group 1 showed significantly higher LVEDP (18.1 mmHg) compared to Group 2 (8.5 mmHg) (P < 0.000).
- Group 1 had a lower LVEF (57.6%) than Group 2 (63.9%) (P < 0.05).
- No significant differences in thallium abnormalities, age, or sex were observed between groups; however, Group 1 included more patients with cardiovascular risk factors.
Conclusions:
- Patients with abnormal thallium stress tests and normal coronary arteries may represent two distinct groups.
- One group exhibits impaired diastolic and systolic function, potentially indicating coronary flow disturbances.
- The other group shows normal cardiac function, suggesting a true false positive thallium stress test.
Abstract:
Left ventricular end-diastolic pressure at rest, left ventricular ejection fraction, thallium segmental abnormalities, as well as sex, age and presence of diabetes mellitus, hypertension, hypercholesterolemia and smoking excess were analyzed in 40 patients with abnormal thallium stress test and normal coronary angiograms. Of these patients, 25 had elevated left ventricular end-diastolic pressure and "low normal" ejection fraction (group 1), while the other 15 had normal left ventricular end-diastolic pressure and "high normal" ejection fraction (group 2). The left ventricular end-diastolic pressure was 18.1 +/- 4.5 mm Hg in group 1 vs. 8.5 +/- 2.4 mm Hg in group 2 (P < 0.000). The ejection fraction was 57.6 +/- 8.3% in group 1 vs. 63.9 +/- 9.1% in group 2 (P < 0.05). There was no difference between the groups in relation to the abnormal segment on thallium stress tests, aged and sex. Although the number of patients was too small for meaningful statistical analysis, most of the patients with diabetes mellitus, hypertension, hypercholesterolemia or smoking history were in group 1. Thus, the patient population with abnormal results on radionuclide exercise tests and angiographically normal coronary arteries probably comprises two groups: a) patients with decreased diastolic and relatively decreased systolic performances which might reflect coronary flow disturbances, and b) patients with normal diastolic and systolic performances, probably reflecting "true false positive thallium stress test".