Mechanical dyssynchrony defined by phase analysis from GSPECT:Does it predict all cause and cardiovascular mortality?

Abstract

Objective: To determine whether mechanical dyssynchrony detected by phase analysis of GSPECT MPI can identify patients with Coronary Disease (CAD) at increased risk of All-Cause Death (ACD) and/or Cardiovascular Death (CVD). Methods: We identified all patients with angiographically significant CAD and a GSPECT MPI in the Duke Databank for Cardiovascular Disease (July 2003 and August 2009). The range of time during which 95% of the left ventricle is initiating contraction phase bandwidth (PB) and the degree of heterogeneity in the distribution of segmental initiation of mechanical contraction (phase standard deviation (PSD)) by GSPECT MPI were measured. To evaluate the relationship between each measure of dyssynchrony and long-term survival, Cox proportional hazards models were fitted. Results: A total of 1428patients were identified. The median age was 64 (interquartile range (IQR) 55-72) years. A majority were male (69.6%), were white (73.7%), and had hypertension (76.2%). A minority had chronic obstructive pulmonary disease (6.6%), congestive heart failure (24.2%), diabetes mellitus (36.2%), peripheral vascular disease (10.4%), prior myocardial infarction (32.9%), or renal insufficiency (5.4%). The median duration follow-up was 4.2 (IQR 2.8-6.3) years. A total of 377 deaths were observed. After adjustment for standard clinical covariates, PB and PSD were significantly associated with ACD and CVD. Among patients with LVEF>35% PB was able to further identify patients at a higher risk for ACD and/or CVD (TABLE). View this table: Conclusions: Mechanical dyssynchrony detected by phase analysis of GSPECT MPI can identify patients with CAD at signifincatly increased risk of ACD and CVD. Moreover, PB is associated with adverse outcomes among patients with LVEF > 35% and may help identify patients who do not meet current criteria for cardiac resynchronization therapy that may benefit from device placement.