title: The effect of beta blockade on single photon emission computed tomographic (SPECT) thallium-201 images in patients with coronary disease.
abstract: We evaluated the effect of beta blockers on thallium-201 (Tl-201) single photon emission computed tomographic (SPECT) imaging in 12 patients with coronary disease using an automated computer algorithm. Maximal exercise heart rate and blood pressure were reduced and exercise time was increased with beta blockers. Estimated stress defect size decreased from 47 +/- 36.3 gm during placebo treatment to 32 +/- 27.1 gm during beta blocker therapy (-32%; p less than 0.01). The placebo treatment redistribution defect was estimated to be 28 +/- 29.8 gm. It fell to 15 +/- 23.3 gm with beta blockade (-46%; p less than 0.005). All patients had a stress Tl-201 defect during placebo treatment and eight had redistribution defects consistent with residual scar. During beta blocker therapy, 2 of 12 patients had normal stress-redistribution studies and only five patients had redistribution defects. Beta blockade can reduce exercise and redistribution Tl-201 SPECT defect size significantly while simultaneously increasing exercise time and reducing angina. Beta blockers may unmask or may eliminate evidence of redistribution. Tl-201 SPECT imaging may be useful in defining the reduction in ischemia produced by cardiac drugs.
authors.affiliation: Department of Medicine, Harbor-UCLA Medical Center, Torrance 90509.
authors.forename: K A
authors.initials: KA
authors.lastname: Narahara
authors.forename: C J
authors.initials: CJ
authors.lastname: Thompson
authors.forename: J F
authors.initials: JF
authors.lastname: Hazen
authors.forename: M
authors.initials: M
authors.lastname: Brizendine
authors.forename: I
authors.initials: I
authors.lastname: Mena
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology* / Q000627:therapeutic use; D000465:Algorithms; D015784:Betaxolol; D001794:Blood Pressure / Q000187:drug effects; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000503:physiopathology; D015444:Exercise; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D011412:Propanolamines / Q000494:pharmacology / Q000627:therapeutic use; D011433:Propranolol / Q000494:pharmacology / Q000627:therapeutic use; D013794:Thallium Radioisotopes; D014055:Tomography, Emission-Computed
chemical_list: D000318:Adrenergic beta-Agonists; D011412:Propanolamines; D013794:Thallium Radioisotopes; D011433:Propranolol; D015784:Betaxolol