Left ventricular dyssynchrony assessed by gated SPECT phase-analysis is an independent predictor for death in patients with known coronary artery disease

Objectives ECG-gated SPECT myocardial perfusion imaging (MPI) allows the assessment of left ventricular (LV) mechanical dyssynchrony (LVMD) using phase analysis of myocardial wall movement. Aim of the study was to evaluate the prognostic value of LVMD in comparison to other established prognostic markers regarding long-term survival in a cohort of patients with known coronary artery disease (CAD) and decreased LV function.

Methods 135 patients (114 men, 64.3 ± 11.0 years) with known CAD (CAD 1 = 28; CAD 2 = 31; CAD 3 = 76) underwent MPI between 2001 and 2010. Beside the assessment of the total perfusion defect at rest (TPD) and the LV ejection fraction (LVEF) a phase histogram using QGS2012 software package (Cedars Sinai, LA, USA) was calculated. A histogram bandwidth > 2 standard deviation (SD) and/or a histogram SD > 2SD compared to published normal values were regarded as presence of LVMD. During follow-up (5.2 ± 0.3 yrs) death of any cause was the endpoint of the study. Kaplan-Meier curves as well as uni- and multivariate COX proportional hazard models were calculated to identify independent predictors for death.

Results 30 deaths were registered (21 cardiac deaths and nine of any other cause). Patients with LVEF ≥ 30% as well as patients with no presence of LVMD showed significant longer survival time than other patient subgroups (for both logrank-test p <0.05). The combination of LVEF < 30% and presence of LVMD showed significant shorter survival time (logrank p<0.05). The variables LVEF, QRS duration, known diabetes mellitus, TPD ≥ 20% and presence of LVMD were included into the COX model. LVEF < 30%, TPD ≥ 20% and presence of LVMD turned out to be independent predictors for death in both uni- and multivariate COX model.

Conclusions In patients with known CAD and decreased LV function the presence of LVMD assessed by MPI is an independent predictor for death