C h a p t e r 4 Prognostic value of gated SPECT in patients with a left bundle branch block

Background. The aim of this study was to assess the prognostic value of technetium-99m tetrofosmin gated SPECT imaging in patients with left bundle branch block (LBBB) using quantitative gated single photon emission computed tomography (SPECT) imaging. Methods and Results. We followed 101 consecutive patients with LBBB using technetium99m tetrofosmin gated SPECT imaging. Average follow-up was 1.24 years (max. 2.48). Hard endpoints were all-cause death and acute myocardial infarction. Event-free survival curves were obtained. Optimal cut-off points for LV volumes and LVEF to predict outcome were determined by ROC curve analysis. Of the patients, 94 had an abnormal study. Fifteen hard events occurred (13 deaths). Perfusion abnormalities were similar for patients with or without events. For LV function parameters the survival curves were maximally separated when we used cutoff values of 160 ml or greater for end-diastolic volume (p=0.019 and hazard ratio [HR] of 1.04 for hard events, p=0.024 and HR 1.04 for all-cause death), 100 ml or greater for end-systolic volume (p=0.043 and HR of 1.04 for hard events, p=0.062 and HR of 1.04 for allcause death), and lower than 35% for LVEF ( p=0.013 and HR of 0.81 for hard events, p=0.047 and HR of 0.81 for all-cause death). Conclusion. By use of quantitative gated SPECT imaging, LBBB patients with an end-diastolic volume of 160 ml or greater, end-systolic volume of 100 ml or greater, or LVEF lower than 35% are at increased risk for subsequent cardiac events. 58