Left ventricular mechanical synchrony from stress and rest 82Rb PET myocardial perfusion ECG-gated studies: differentiating normal from LBBB patients.

BACKGROUND: We have previously reported normal values for LV mechanical synchrony from post-stress exercise (99m)Tc SPECT studies; the goal of this study was to develop normal values for mechanical synchrony from pharmacologic stress and rest (82)Rb PET studies and compare these values to a population of LBBB patients.

METHODS AND RESULTS: The normal population consisted of 40 patients with a low likelihood of coronary artery disease. The LBBB population consisted of 23 patients with ECG evidence of LBBB. All patients were imaged with pharmacologic stress and processed using SyncTool™ (Emory Cardiac Toolbox™). Means and standard deviations were calculated for the stress and rest phase parameters. Normal male and female phase standard deviation were 15.0 ± 7.0 and 13.2 ± 7.7, respectively, for stress (P = NS), and 22.7 ± 13.2 and 16.6 ± 14.3 for rest (P = NS). Normal male and female histogram bandwidth were 38.1 ± 13.3 and 32.0 ± 13.5, respectively, for stress (P = NS) and 50.8 ± 18.7 and 44.4 ± 44.9 for rest (P = NS). ROC analysis yielded a sensitivity/specificity as high as 80%/90% for males, and 92%/75% for females (P = NS).

CONCLUSIONS: Normal values for LV mechanical synchrony have been developed for (82)Rb pharmacologic stress and rest PET studies; furthermore, the stress pharmacologic values do not differ significantly from our previously reported exercise post-stress SPECT normal values. Finally, ROC analysis confirmed that these normal values were able to differentiate normal and LBBB populations.