Prevalence of Left Ventricular Dyssynchrony in Individuals Undergoing Gated SPECT Myocardial Perfusion Imaging Using Phase Analysis

Left ventricular (LV) synchrony is a clear indicator of cardiac performance. However, left ventricular dyssynchrony (LVD) is not necessarily a sign of heart malfunction. Individuals at a higher risk of developing heart failure can be identified by LVD. Gated SPECT myocardial perfusion imaging (MPI) allows the simultaneous assessment of LV perfusion, function, and mechanical dyssynchrony through phase analysis. The aim of this study was to evaluate the prevalence and predictors of LVD in patients undergoing MPI. A total of 907 consecutive patients referred to the Nuclear Medicine Department of Farshchian Heart Center, Hamadan, Iran, for diagnostic purposes were examined. The patients underwent gated SPECT MPI with a 2-day stress/rest protocol. Auto-Quant software package was used to evaluate perfusion, function, and phase analysis. Additionally, significant LVD was assessed based on the following criteria: standard deviation of the LV phase distribution > 19.6 and a phase histogram > 72.5 in the stress phase of the examination. Several variables were evaluated using univariate and multivariate analyses. The variables significantly associated with LVD were sex (male), obesity, hypertension, diabetes, QRS > 120 ms, a history of coronary artery disease, myocardial perfusion defects reported on MPI, and LV dysfunction. Our results suggested that the prevalence of significant LVD as a predictor of adverse cardiovascular events, death, and progression to heart failure was 12.9%. The multivariate analysis revealed that variables such as obesity, diabetes, hypertension, sex (male), coronary artery disease, and QRS >120 ms were highly associated with LVD.