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Thallium-201 exercise scintigraphy in patients having complete left bundle branch block with normal coronary arteries
Insights
Left bundle branch block can cause abnormal heart scans that mimic coronary artery disease. These reversible defects on thallium-201 scintigraphy may result from functional ischemia, not blocked arteries.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Diagnostic Imaging
Background:
- Left bundle branch block (LBBB) can complicate the diagnosis of coronary artery disease (CAD).
- Thallium-201 exercise scintigraphy and echocardiography are commonly used to assess myocardial perfusion and function.
- Interpreting these tests in LBBB patients requires careful consideration of potential confounding factors.
Purpose of the Study:
- To investigate the cause of reversible anteroseptal defects seen on thallium-201 scintigraphy in patients with LBBB and chest pain.
- To differentiate between true CAD and functional abnormalities in this patient population.
Main Methods:
- Analysis of eleven patients with LBBB and chest pain suggestive of CAD.
- Utilized thallium-201 exercise scintigraphy, M-mode echocardiography, and coronary arteriography.
- Coronary arteriography served as the gold standard for assessing coronary artery patency.
Main Results:
- Coronary arteriography revealed normal coronary arteries in all eleven patients.
- Eight patients exhibited a reversible anteroseptal defect on thallium-201 scintigraphy.
- These eight patients also showed asynchronous septal motion on echocardiography.
Conclusions:
- Reversible anteroseptal defects on thallium-201 scintigraphy in LBBB patients with chest pain do not necessarily indicate coronary artery disease.
- Abnormal septal motion in LBBB may lead to functional ischemia, causing these scintigraphic defects.
- Echocardiography can help identify abnormal septal motion, aiding in the correct interpretation of myocardial perfusion imaging.
Abstract:
Eleven patients with left bundle branch block and chest pain suggestive of coronary arterial disease were analyzed using thallium-201 exercise scintigraphy, M-mode echocardiography and coronary arteriography. The coronary arteries were shown to be normal in all patients. A reversible anteroseptal defect on thallium-201 scintigraphy and an asynchronous septal motion on echocardiography were evident in eight patients. Thus, symptomatic patients with left bundle branch block may have reversible anteroseptal defects on thallium-201 scintigraphy which do not indicate coronary artery disease. Rather, they may be due to functional ischemia secondary to abnormal septal motion.