Abstract 13863: Left Ventricular Dyssynchrony during Lower Leg Positive Pressure Assessed by Real-time 3-dimensional Echocardiography
Introduction: Dyssynchronous myocardial contraction influences left ventricular (LV) function and is associated with a poor prognosis in heart failure. However, it is not elucidated whether loading condition influences LV dyssynchrony.
Hypothesis: We hypothesized that the dyssynchrony in dilated hearts is depend on preload and the dependency may affect the response of cardiac output during preload augmentation.
Methods: A total of 16 dilated cardiomyopathy (DCM) patients (63±6 years old) and 20 age matched healthy control patients (68±6 years old) underwent echocardiography. Real-time 3 dimensional echocardiography (RT3DE) was performed during 90 mmHg of leg positive pressure (LPP). The regional volume time curves were derived for 16 segments of the LV from 3D data set. The standard deviation of the time to the regional LV minimum systolic volume (Tmsv) for all 16 segments (Tmsv 16-SD) was assessed as an asynchrony index. This parameter was expressed as a percentage of the RR interval. LV end-diastolic and end-systolic volumes (EDV, ESV), stroke volume (SV) and ejection fraction (EF) were also evaluated.
Results: In control patients with normal LV function (EF >60%), preload stress did not influense the LV asynchrony index (1.6±0.7% vs.1.4±0.5%, ns). EDV, ESV and SV increased in control group, while EF did not change. In contrast, LV asynchrony index increased during LPP (Tmsv 16-SD: 3.6±2.2% vs.7.6±2.9%, p<0.01), EDV and ESV increased, and EF decreased in DCM patients with low LV function (EF<45%). Figure shows an example of parametric imaging of Tmsv 16-SD at baseline and during LPP.
Conclusions: In DCM patients, preload stress worsened the magnitude of LV dyssynchrony, and the deterioration in ventricular synchrony during preload augmentation was associated with reduction in stroke volume. Lording condition should be considered when one selects candidate for cardiac resynchronization therapy by evaluating LV dyssynchrony in DCM patients.
- © 2010 by American Heart Association, Inc.