Gated blood pool SPECT assessment of changes in ventricular function and dyssynchrony in patients responding to cardiac resynchronization therapy

Objectives The assessment of dyssynchrony in heart failure patients remains challenging. The use of fully automated software removes operator-induced variability from the serial analysis of images. The aim of this study was to evaluate changes in function and dyssynchrony measures obtained from gated blood pool single photon emission computed tomography (GBPS ) images using Cedars-Sinai's QBS software in patients who responded to cardiac resynchronization therapy (CRT).

Methods Sixteen patients were studied. Thirteen responders to CRT were identified at follow-up time using exercise tolerance and quality of life improvement criteria. Average follow-up time was 152 days (SD: 102, range: 56-444). Left-ventricular (LV) and right-ventricular (RV) ejection fractions (EF), end-systolic volumes (ESV), and intra- and inter-ventricular dyssynchrony measures were computed (intra: phase histogram standard deviation Σ, bandwidth β, and entropy ; inter: absolute difference of mean LV and RV phase |Δμ|). The statistical significance of differences between the pre- and post-CRT values was calculated using the Wilcoxon matched pairs test.

Results Among responders, LV EF, LV ESV, LV intra-ventricular and LV-RV inter-ventricular synchrony improved significantly. RV changes were not statistically significant.

Conclusions GBPS has the potential to provide objective assessment of function and dyssynchrony changes. Further work is needed to assess the predictive value of GBPS to select patients for CRT.