Original Research
LV Mechanical Dyssynchrony in Heart Failure With Preserved Ejection Fraction Complicating Acute Coronary Syndrome

https://doi.org/10.1016/j.jcmg.2011.01.011Get rights and content
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Objectives

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.

Key Words

acute coronary syndrome
diastolic heart failure
echocardiography
mechanical dyssynchrony

Abbreviations and acronyms

A
peak velocity of the late filling wave due to atrial contraction
ACS
acute coronary syndrome
DT
deceleration time
E
peak mitral inflow velocity of the early rapid-filling wave
EF
ejection fraction
Em
mean early diastolic velocity of 6 basal left ventricular myocardial segments
HF
heart failure
HFPEF
heart failure with preserved ejection fraction
LV
left ventricular
Sm
peak systolic velocity of 6 basal left ventricular myocardial segments
TDI
tissue Doppler imaging
Te
time to peak myocardial early diastolic velocity
Te-SD
SD of the time to peak early diastolic velocity of 12 myocardial segments
Ts
time to peak myocardial systolic velocity during the LV ejection period
Ts-SD
SD of the time to peak systolic velocity of 12 myocardial segments
WMSI
wall motion score index

Cited by (0)

This study was supported by the Research Grant Council of Hong Kong (grant reference number: 477907). The authors have reported that they have no relationships to disclose.