Value of Assessment of Dyssynchrony as a Quantitative Indicator of Right Ventricular Free Wall function by Gated Blood Pool SPECT (GBPS) in pre-LVAD patients

Objectives: Evaluation of RV function prior to LVAD is key to prognostication and surgical planning. Regional RV free wall (RVFW) function may be particularly important after LVAD due to septal shift toward the decompressed LV. We have previously shown feasibility of pre-LVAD GBPS (automated, count-based, without geometric assumptions) and the additive value of RV regional function assessment over global RVEF. However, subjective analysis of RV regional function is limited by the complexity of RV contraction. Here, we explored the utility and additive value of RVFW dyssynchrony measurement using phase analysis as a quantitative parameter of RV regional function.

Methods: GBPS was performed using standard procedure on 25 patients awaiting LVAD. Global and regional RV function was assessed. The phase standard deviation (PSD) of the RVFW (non-septal portion of RV) was generated automatically. RV failure was defined as requiring RV assist device or requiring greater than 14 consecutive days of postoperative inotropic support after LVAD implant.

Results: 25 patients are included in the analysis (mean age 57 years, 84% male, 76% white). 16 patients had a regional wall-motion abnormality within the RVFW. The RVFW-PSD was significantly higher in patients with a regional wall-motion abnormality (61.1 ± 31.7 ms vs. 37.9 ± 13.4 ms, p=0.048). Of the 16 patients with a regional wall-motion abnormality, patients with RVFW-PSD greater than the mean (61.1 ms) were also more likely to experience RV failure (4/8=50.0% vs. 1/8=12.5%) [Figure 1]. No patients without a regional wall-motion abnormality had RV failure.

Conclusion: Heart failure patients with RVFW regional wall-motion abnormalities and dyssynchrony are more likely to develop RV failure after LVAD implantation. Quantitative estimation of regional RV electromechanical function by GBPS RV phase analysis is a novel and potentially valuable application of nuclear cardiology. Research Support: None. $$graphic_49DE4AF6-1369-4D70-9B0E-32E56D1B640E$$