title: LV mechanical dyssynchrony in heart failure with preserved ejection fraction complicating acute coronary syndrome.
abstract: OBJECTIVE
  The aim of this study was to evaluate the role of left ventricular (LV) mechanical dyssynchrony in heart failure with preserved ejection fraction (HFPEF) complicating acute coronary syndrome (ACS).
  
  
  BACKGROUND
  In systolic heart failure, LV mechanical dyssynchrony worsens cardiac function and cardiac resynchronization therapy improves clinical outcome. The role of LV mechanical dyssynchrony in HFPEF complicating ACS is unknown.
  
  
  METHODS
  One hundred two patients presenting with ACS (ejection fraction ≥50%) and 104 healthy controls were studied using tissue Doppler imaging: group 1 (n = 55) had HFPEF on presentation and group 2 (n = 47) had no clinical HFPEF. The SD of time to peak systolic myocardial velocity and the SD of early diastolic (Te-SD) myocardial velocity of 12 LV segments were obtained for evaluation of dyssynchrony. Longitudinal mean myocardial ejection systolic velocity (mean Sm) and mean early diastolic velocity (mean Em) were measured.
  
  
  RESULTS
  Te-SD was greater in group 1 (33 ± 13 ms) than group 2 (21 ± 9 ms) (p < 0.001), and diastolic mechanical dyssynchrony was evident in 35% of patients in group 1 but in only 9% in group 2 (p < 0.001). Conversely, the SD of time to peak systolic myocardial velocity was similar in the 2 ACS groups (34 ± 16 ms vs. 32 ± 18 ms; p = NS), showing a similar prevalence of systolic mechanical dyssynchrony (47% vs. 43%; p = NS). Worsening of the diastolic dysfunction grade was associated with a parallel increase in Te-SD (grades 0, 1, 2, and 3: 16 ± 3 ms, 21 ± 5 ms, 28 ± 9 ms, and 41 ± 17 ms, respectively; p < 0.001). Te-SD correlated negatively with mean Em (r = -0.56, p < 0.001) and positively with peak mitral inflow velocity of the early rapid-filling wave/Em (r = 0.69, p < 0.001); mean myocardial ejection systolic velocity correlated significantly with mean Em (r = 0.56, p < 0.001), SD of time to peak systolic myocardial velocity (r = -0.42, p < 0.001) and Te-SD (r = -0.23, p = 0.001). Multivariate analysis identified peak mitral inflow velocity of the early rapid-filling wave/Em as the only variable independently associated with HFPEF (odds ratio: 1.48, p = 0.001). When peak mitral inflow velocity of the early rapid-filling wave/Em was excluded from the model, Te-SD (odds ratio: 1.13, p < 0.001) and mean Em (odds ratio: 0.37, p < 0.001) became independently associated with HFPEF.
  
  
  CONCLUSIONS
  LV diastolic mechanical dyssynchrony may impair diastolic function and contribute to the pathophysiology of HFPEF, complicating ACS.
authors.affiliation: Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Alex Pui-Wai
authors.initials: AP
authors.lastname: Lee
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.forename: Gabriel
authors.initials: G
authors.lastname: Yip
authors.forename: Fang
authors.initials: F
authors.lastname: Fang
authors.forename: Yu-Jia
authors.initials: YJ
authors.lastname: Liang
authors.forename: Jun-Min
authors.initials: JM
authors.lastname: Xie
authors.forename: Yat-Yin
authors.initials: YY
authors.lastname: Lam
authors.forename: Cheuk-Man
authors.initials: CM
authors.lastname: Yu
mesh_terms: D054058:Acute Coronary Syndrome / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D000368:Aged; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D015150:Echocardiography, Doppler; D005260:Female; D054143:Heart Failure, Systolic / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D006723:Hong Kong; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D016017:Odds Ratio; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013318:Stroke Volume; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D016277:Ventricular Function, Left