Phase analysis for the assessment of left ventricular dyssynchrony by Gated Myocardial Perfusion SPECT. Importance of clinical and technical parameters

Introduction: Phase analysis (PA) of the left ventricle is a new tool in nuclear cardiology studies used to assess left ventricular mechanical timing based on different clinical applications. However, the use of this tool is relatively unknown. Objective: To expose the feasibility of the new PA tool in myocardial perfusion (Gated-SPECT) to assess left ventricle mechanical timing, and to verify the differences between values depending on clinical and technical conditions. Materials and methods: The study included consecutive patients evaluated by Gated-SPECT. The main variables were different depending on clinical and technical conditions. PA was assessed using the PHASE tool of the QPS-QGS program (Cedars-Sinai Medical Center, Los Angeles, USA). The following parameters were obtained: histogram bandwith (HB), standard deviation (SD) and entropy (E). A descriptive and analytical analysis of means and/or medians was performed using parametric or non-parametric tests. Statistical significance was p <0.05. IBM-SPSS V21® was used. Results: 300 patients were included in this study with a mean age of 65±12.7. No differences were found in relation to the study phase (stress-rest) [HB (p=0.4), SD (p=0.6), E (p=0.8)], stress type [HB (p=0.38), SD (p=0.8), E (p=0.06), E (p=0.06)], dose used [HB (p=0.19), SD (p=0.05), E (p=0.06)], gamma camera [HB (p=0.02), SD (p=0.06), E (p=0.08)], or history of coronary heart disease [HB (p=0.44), SD (p=0.18), E (p=0.17)]. Furthermore, differences in conduction disorders were observed [HB (p=0.001), SD (p=0.02), E (p=0.001)], ejection fraction < or >35% (p=0.001), E (p=0.001)] normal or necrosis study [HB (p=0.001), SD (p=0.001), E (p=0.001)], and gender [HB (p=0.002), SD (p=0.006), E (p=0.005)]. Conclusions: The new PA tool of nuclear medicine is feasible in our context. The type of stress, the administered dose, the study phase or the gamma camera used did not affect the parameters. However, gender, interventricular conduction disorders, necrosis and systolic dysfunction did have an impact on them