gated 99mtc-mibi myocardial perfusion spect in patients with right bundle branch block but without evidence of coronary artery disease

introduction: we aimed to investigate the effect of right bundle branch block (rbbb) on perfusion and functional parameters in dipyridamole stress/rest tc99m-mibi gated myocardial perfusion spect (gspect) which may be helpful in interpretation of myocardial perfusion imaging. methods: we studied 73 patients with low pre-test likelihood of coronary artery disease in two groups:  38 patients with rbbb and 35 subjects with normal ecg. both groups underwent two-day dipyridamole stress–rest tc99m-mibi gspect. two groups were matched. there was no significant difference in sex and age variable between two groups. results: visual calculated sss and srs in all patients were between 0 and 3. regarding the prone images, diaphragmatic attenuation and breast attenuation, all patients gspect findings were within normal limits. there was no significant difference in tid ratio between two groups:  rbbb group: tid ratio= 1.02±0.16 and control group: tid ratio= 0.96±0.14 (p=0.09). there was no significant difference in left ventricular end-systolic volume, end-diastolic volume, ejection fraction, summed stress and rest motion & thickening scores between rbb patients group and control group. no regional lv wall motion abnormality was noticed in any patient in either group. conclusion: high normality rate of the lv myocardial perfusion and functional indices in the presence of rbbb was noticed in gated dipyridamole stress/rest tc-99m sestamibi myocardial perfusion spect.  no remarkable false positive perfusion findings or abnormal lv functional indices acquired by gspect in this group of patients.