Left bundle branch block and coronary artery disease: Accuracy of dipyridamole thallium-201 single-photon emission computed tomography in patients with exercise anteroseptal perfusion defects
- 76 Downloads
Reduced septal or anteroseptal uptake of thallium-201 during exercise is frequently observed in patients with left bundle branch block (LBBB) even in the absence of left anterior descending (LAD) coronary artery disease. The purpose of this study was to evaluate prospectively the accuracy of dipyridamole201TI single-photon emission computed tomography (SPECT) in detecting LAD coronary artery disease in patients with LBBB and septal or anteroseptal perfusion defects on exercise201TI SPECT.
Methods and Results
Twelve consecutive patients (10 men and two women) with complete LBBB and septal or anteroseptal perfusion defects on exercise201TI SPECT underwent dipyridamole201TI SPECT. The delay between dipyridamole and exercise was 2 to 30 days. Coronary angiography was performed during this period in all patients. Six (50%) of 12 patients with exercise perfusion defects showed normal perfusion after dipyridamole; all had normal coronary angiograms. The remaining six patients also had positive results of dipyridamole studies, two with moderate and four with severe septal or anteroseptal perfusion defects. Coronary angiography showed significant (>50%) LAD coronary artery stenosis in three patients; three patients with severe septal or anteroseptal perfusion defects after dipyridamole had normal coronary angiograms. Neither the evaluation of apical involvement nor the presence of dilated ventricles, decreased left ventricular ejection fraction, or wall motion abnormalities could help to identify (or explain) false-positive results.
This study confirms that dipyridamole is more accurate than exercise in excluding LAD coronary artery disease. However, there are still false-positive results and the severity of the septal or anteroseptal perfusion defect does not add additional information to identify LAD coronary artery disease. Coronary angiography is thus necessary for positive dipyridamole study results to identify coronary artery disease as a major prognostic factor in patients with LBBB.
Key Wordsleft bundle branch block dipyridamole thallium-201 single-photon emission computed tomography coronary artery disease
Unable to display preview. Download preview PDF.
- 4.Rothbart MR, Beller GA, Watson DD, Nygaard TW, Gibson RS. Diagnostic accuracy and prognostic significance of quantitative thallium-201 scintigraphy in patients with left bundle branch block. Am J Noninvas Cardiol 1987;1:197–205.Google Scholar
- 14.Morais J, Soucy JP, Sestier F, Lamoureux F, Lamoureux J, Danais S. Dipyridamole testing compared to exercise stress for thallium-201 imaging in patients with left bundle branch block. Can J Cardiol 1990;1:5–8.Google Scholar
- 19.Pope DL, Parker DL, Gustafson DE, Clayton PD. Dynamic search algorithms in left ventricular border recognition and analysis of coronary arteries. Comp Cardiol 1984;4:71–5.Google Scholar
- 20.Hodge J, Mattera J, Fetterman R, Williams B, Wackers FJ. False positive TL-201 defects in left bundle branch block: relationship to left ventricular dilatation. J Am Coll Cardiol 1987;9:137A.Google Scholar
- 26.Altehoefer C, Vom Dahl J, Bull U. Falsch-positiver Befund in der99mTc-MIBI SPECT bei Linksschenkelblock und angiographisch ausgeschlossener KHK. Nucl Med 1994;33:46–8.Google Scholar
- 27.Iskandrian AS, Verani MS. Nuclear cardiac imaging: principles and applications. Philadelphia: FA Davis, 1996:114–7.Google Scholar