A comparison of dobutamine and maximal exercise as stress for thallium scintigraphy.
In the assessment and evaluation of patients with suspected coronary artery disease there is a need for pharmacological stress combined with thallium scintigraphy. Thallium images were obtained following stress both with dobutamine infusion (5-20 micrograms kg-1 min-1) and with symptom-limited bicycle ergometry in 20 patients (age 39-70 years) with chest pain who had been admitted for coronary angiography. Percentage thallium uptake was calculated using a region of interest technique. Detailed comparison was performed of the presence, size and distribution of left ventricular thallium perfusion defects; the percentage thallium uptake in ventricles, lung and liver; and the haemodynamic response to stress. Each stress produced a similar number of abnormal segments in each of three views (total EX 166/300; DOB 167/295), but exercise produced larger defects in the anterior view (P < 0.025). Thallium uptake in left and right ventricles and relative uptake to lungs were similar, but dobutamine produced higher relative liver uptake [EX 1.55 (0.67); DOB 2.97 (1.23) P < 0.0001]. Fourteen patients were able to tolerate dobutamine 20 micrograms kg-1 min-1. The ratio of peak stress to rest double product was smaller with dobutamine in both patients with (DOB 1.3; EX 2.0; P < 0.0047) and patients without beta-blockade (DOB 1.5; EX 2.4; P < 0.008). Dobutamine produced fewer conventional stress endpoints of chest pain and ST depression. In conclusion, dobutamine produces a well-tolerated incremental pharmacological stress with thallium images similar to maximal exercise, and provides a useful alternative stress in patients unable to perform adequate dynamic exercise.
Department of Medical Cardiology, Royal Infirmary, Glasgow, UK.
D R
DR
Wallbridge
A C
AC
Tweddel
W
W
Martin
I
I
Hutton
D017023:Coronary Angiography; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D004280:Dobutamine; D004562:Electrocardiography; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D013794:Thallium Radioisotopes
D013794:Thallium Radioisotopes; D004280:Dobutamine