Defect images in stress thallium-201 myocardial scintigraphy in patients with complete left bundle branch block: comparison of exercise stress and pharmacological stress.
OBJECTIVE
Stress thallium-201 (201Tl) myocardial scintigraphy can demonstrate perfusion abnormalities, especially in the septum in patients with complete left bundle branch block (CLBBB) even with angiographically normal coronary arteries. Differences in the images between exercise and pharmacological stress 201Tl myocardial scintigraphy were evaluated in patients with CLBBB and normal coronary arteries.


METHODS
Forty-five patients with CLBBB underwent exercise stress using treadmill or pharmacological (adenosine triphosphate) stress 201Tl myocardial scintigraphy from October 1997 to February 2003. Patients with myocardial diseases were excluded, such as cardiomyopathy and coronary artery diseases detected by echocardiography and/or cardiac catheterization. The myocardial segment was classified according to the American Heart Association style for coronary artery disease.


RESULTS
Peak blood pressure levels and heart rates were significantly higher in the exercise stress group than in the pharmacological stress group (p < 0.001). The rate of defects in stress images was significantly higher in the exercise stress group (72.4%; 21/29 cases) than in the pharmacological stress group (18.8%; 3/16 cases) (p < 0.01). The rate of redistribution of observed defects in delayed images was 76.2% (16/21 cases) in the exercise stress group, and 0% (0/3 cases)in the pharmacological stress group (p < 0.01). The myocardial segments showing defects were different between the exercise stress group and the pharmacological stress group.


CONCLUSIONS
Patients with CLBBB showed different frequencies of defects by stress 201Tl myocardial scintigraphy according to the stress method. Moreover, defects also occured in areas other than the septum. Blood pressure and heart rate were involved in the mechanisms of defects in left bundle branch block.
Sasaki
Hideki
H
Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Nishi-shinbashi, Minato-ku, Tokyo. hsasaki@jikei.ac.jp
Shimizu
Mitsuyuki
M
Ogawa
Kazuhiko
K
Okazaki
Fumiko
F
Mizokami
Tsuneo
T
Kusaka
Masafumi
M
Uehara
Yoshiki
Y
Taniguchi
Ikuo
I
Mochizuki
Seibu
S
D000255:Adenosine Triphosphate; D000368:Aged; D001794:Blood Pressure; D002037:Bundle-Branch Block / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017023:Coronary Angiography; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon
D013794:Thallium Radioisotopes; D000255:Adenosine Triphosphate