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Reverse redistribution of thallium-201 represents a low-risk finding in thrombolysed patients following myocardial
B S Sridhara1, E Dudzic, S Basu
1Department of Cardiology, Northwick Park Hospital and Clinical Research Centre, Harrow, Middlesex, UK.
Insights
Reverse redistribution on thallium-201 imaging in post-myocardial infarction patients indicates viable myocardium and better exercise capacity. This finding suggests potential for improved outcomes in patients receiving thrombolytic therapy.
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Thrombolytic therapy is a standard treatment for acute myocardial infarction.
- Assessing myocardial viability post-infarction is crucial for patient management.
- Thallium-201 (201Tl) imaging is used to evaluate myocardial perfusion and viability.
Purpose of the Study:
- To determine the prevalence of reverse redistribution on 201Tl imaging.
- To assess the clinical significance of reverse redistribution in patients post-myocardial infarction treated with thrombolysis.
- To correlate reverse redistribution with exercise capacity and left ventricular function.
Main Methods:
- Sixty-two patients with myocardial infarction treated with thrombolysis underwent stress and delayed 201Tl imaging.
- Radionuclide ventriculography was performed to assess left ventricular ejection fraction and wall motion.
- Coronary angiography was performed in a subset of patients.
Main Results:
- Reverse redistribution was observed in 21 patients (34%).
- Patients with reverse redistribution showed significantly higher exercise capacity (P < 0.01).
- Regions with reverse redistribution had less regional wall motion abnormality (P < 0.01) and suggested viable myocardium.
Conclusions:
- Reverse redistribution on 201Tl imaging is prevalent in post-myocardial infarction patients treated with thrombolysis.
- This pattern is associated with better exercise capacity and less severe wall motion abnormalities.
- Reverse redistribution suggests the presence of viable myocardium, which is clinically significant for prognosis.
Abstract:
The aim of the study was to evaluate the prevalence and clinical significance of reverse redistribution on thallium-201 imaging in post-myocardial infarction patients who have undergone thrombolytic therapy. Sixty-two patients aged 35-79 (mean 60) years with proven myocardial infarction who had undergone thrombolysis were studied 6 weeks post infarction. Standard stress and 4-h redistribution imaging was performed with 201Tl following treadmill exercise. Separate day rest injection of 201Tl was given after sublingual nitroglycerine; imaging was performed at 1 h. Planar images were acquired in three standard views and semiquantitative segmental analysis of the images was performed from the unprocessed images. All patients had radionuclide ventriculography for the assessment of left ventricular ejection fraction and wall motion abnormality. Thirty-three patients also had coronary angiography. 201Tl scintigraphy revealed fixed defects in 19 patients, reversible defects in 22, and reverse redistribution in 21. Those with reverse redistribution had a significantly higher exercise capacity (P < 0.01). Mean (SD) left ventricular ejection fraction was 46 (12)% for those with fixed defects, 47 (9)% for those with reversible defects and 45 (15)% for patients with reverse redistribution (P = NS). The regional wall motion abnormality score was 8 (5), 11.8 (2.2) and 14.2 (6) respectively in patients with reverse redistribution, redistribution alone and fixed defects. Regions with reverse redistribution revealed less regional wall motion abnormality compared to the other two groups (P < 0.01). Fifteen patients demonstrated significant 201Tl uptake in the region showing reverse redistribution, with rest injection of 201Tl following sublingual nitroglycerine, suggesting viable myocardium in that region.(ABSTRACT TRUNCATED AT 250 WORDS)