Abstract 16620: The Prognostic Value of Mechanical Dyssynchrony Measured by GSPECT MPI versus Electrical Dyssnchrony Measured by QRS Duration Among Patients With an Ejection Fraction >35%
Background: Whether mechanical dyssynchrony measured by phase analysis of gated single-photon emission computed tomography myocardial perfusion imaging (GSPECT MPI) adds prognostic information to electrical dyssynchrony or is is associated with death among patients with an EF >35% is incompletely understood.
Methods: We identified consecutive patients with angiographically significant coronary disease who underwent GSPECT MPI in the Duke Databank for Cardiovascular Disease between July 2003 and May 2009. Serial Cox proportional hazards models consisting of clinical variables only, clinical variables plus electrical dyssynchrony as measured by QRS duration, clinical variables plus mechanical dyssynchrony according to the duration of the cardiac cycle during which 95% of the ventricle is initiating contraction (phase bandwidth),and a final model inclusive of all of these variables were fitted.
Results: A total of 1,157 patients were identified. The median age was 64 (interquartile range (IQR) 55-72 years). Patients were predominantly white (73.8%), of male sex (67.7%), and had hypertension (76.7%). A minority had congestive heart failure (21.9%), peripheral vascular disease (10.5%), and cerebrovascular disease (12.2%). The median QRS duration was 92 (IQR 84-103) ms, while the median bandwidth was 58 (IQR 41-90)°. The median duration of follow-up was 4.3 (IQR 3.0-6.4) years. A total of 293 deaths were observed. Mechanical dyssynchrony added prognostic information independent of standard clinical variables and electrical dyssynchrony (Figure).
Conclusions: Mechanical dyssynchrony measured by GSPECT MPI is independently associated with death and adds prognostic information above that provided by standard clinical covariates and electrical dyssynchrony among patients with an EF>35%. Whether cardiac resynchronization therapy improves outcomes among patients with mechanical dyssynchrony measured by GSPECT requires further study.
Author Disclosures: P.L. Hess: Honoraria; Modest; Sanofi-Aventis. L.K. Shaw: None. S.M. Al-Khatib: None. Z. Samad: None. E.J. Velazquez: Research Grant; Modest; Abbott Laboratories, Evalve, Inc.. Honoraria; Modest; Boehringer Ingelheim. Consultant/Advisory Board; Modest; Gilead Sciences, Inc., Ikaria. C.M. O’Connor: Research Grant; Modest; Roche Diagnostics, GE Healthcare, Johnson & Johnson, Gilead, Otsuka, Amgen, Ostellas. Honoraria; Modest; Actelion. S. Borges-Neto: Research Grant; Modest; GE Healthcare.
- © 2014 by American Heart Association, Inc.