LV mechanical dyssynchrony in heart failure with preserved ejection fraction complicating acute coronary syndrome.

Abstract

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.

• Authors: Alex Pui-Wai Lee, Qing Zhang, Gabriel Yip, Fang Fang, Yu-Jia Liang, Jun-Min Xie, Yat-Yin Lam, Cheuk-Man Yu
• Journal: JACC. Cardiovascular imaging (JACC Cardiovasc Imaging) Vol. 4 Issue 4 Pg. 348-57 (Apr 2011) ISSN: 1876-7591 [Electronic] United States
• PMID: 21492809 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Topics

• Acute Coronary Syndrome (complications, diagnostic imaging, physiopathology)
• Aged
• Case-Control Studies
• Chi-Square Distribution
• Echocardiography, Doppler
• Female
• Heart Failure, Systolic (diagnostic imaging, etiology, physiopathology)
• Hong Kong
• Humans
• Logistic Models
• Male
• Middle Aged
• Myocardial Contraction
• Odds Ratio
• Prospective Studies
• Risk Assessment
• Risk Factors
• Stroke Volume
• Time Factors
• Ventricular Dysfunction, Left (diagnostic imaging, etiology, physiopathology)
• Ventricular Function, Left