Association of left ventricular mechanical dyssynchrony with survival benefit from revascularization: a study of gated positron emission tomography in patients with ischemic LV dysfunction and narrow QRS.
OBJECTIVE
LV mechanical dyssynchrony (LVMD) is a risk marker in narrow QRS cardiomyopathy, but its association with treatment outcome is not well defined. We determined the incremental prognostic value of LVMD in ischemic cardiomyopathy, and assessed its interaction with scar, myocardium in jeopardy and subsequent revascularization.


METHODS
Stress and rest (82)Rb gated PET were performed in 486 consecutive patients (66 ± 11 years of age, 82 % men, LV ejection fraction 26 ± 6 %) with ischemic cardiomyopathy and QRS <120 ms. LVMD was determined as the standard deviation (SD) of the regional time to minimum volume on phase analysis of the gated PET scan. A propensity score was determined to adjust for nonrandomized referral after imaging to coronary artery bypass grafting (CABG). In a Cox proportional hazards model used to determine the association between measures of LVMD and survival time, CABG was included as a time-dependent covariate and the use of an implantable cardiac defibrillator (ICD) after imaging was modeled as a stratification factor.


RESULTS
Over 1.9 ± 1.4 years, 96 patients (20 %) underwent CABG and 108 (22 %) died. LVMD was a predictor of mortality (HR 1.16. 95 % CI 1.03;1.30, per 10° increase in phase SD, p = 0.02) after adjusting for baseline covariates, prior ICD use, the use of postimaging CABG, and other imaging data. There was a significant interaction between phase SD and CABG. Nested Cox models showed that LVMD carried prognostic information incremental to clinical variables, ejection fraction and CABG.


CONCLUSIONS
LVMD is an independent predictor of all-cause mortality in ischemic cardiomyopathy, and may identify patients with a differential survival benefit from CABG versus medical therapy.
Heart and Vascular, Imaging Institute, Cleveland, OH, USA. aljarow@ccf.org
Wael
W
AlJaroudi
M Chadi
MC
Alraies
Rory
R
Hachamovitch
Wael A
WA
Jaber
Richard
R
Brunken
Manuel D
MD
Cerqueira
Thomas
T
Marwick
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging* / Q000401:mortality / Q000601:surgery; D055424:Cardiac-Gated Imaging Techniques; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging*; D009204:Myocardial Revascularization; D049268:Positron-Emission Tomography; D011379:Prognosis; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000401:mortality / Q000601:surgery