Assessment Of Left Ventricular Systolic Synchrony In Dilated Cardiomyopathy Patients With Normal QRS Wave By Pulsed-wave Doppler Tissue Imaging

Objective: Employing the technique of pulsed-wave Doppler tissue imaging (PW-DTI), the purpose of this study is to evaluate the distribution characteristics of left ventricular systolic synchronicity (LV-SS) and dyssynchrony (LV-SD) in dilated cardiomyopathy (DCM) patients with normal QRS wave width and chronic heart failure, to analyze the correlation between DCM left ventricular systolic asynchrony and left ventricular systolic function, ventricular remodeling, and functional mitral regurgitation.Methods: 47 patients of dilated cardiomyopathy with normal QRS wave width and chronic heart failure were randomly recruited as the study group (DCM group), 40 healthy adults were enrolled in this study as the control group. Each subject received a conventional two-dimensional echocardiography for left ventricular ejection fraction (LVEF), left ventricular end diastolic volume (LVEDV) and left ventricular end systolic volume (LVESV). Gaining the maximum mitral regurgitation area (MRA) from the apical four-chamber view on color flow Doppler images, the ratio of MRA to left atrium area (LAA) was calculated (MRA/LAA). Time to peak systolic velocity (Ts) was calculated by PW-DTI in 12 left ventricular segments, from which the standard deviation of Ts in 12 segments (Ts-SD) and maximum Ts difference (Ts-maxD) were compared between two groups. The LV-SD was defined as Ts-maxD > 100ms or Ts-SD >34.4ms in 12 segments. Meanwhile, The occurrence rate of LV-SD and the ventricular distribution of LV delayed systolic in the patients was calculated. Additionally, the correlation analysis was perform between Ts-maxD, Ts-SD and LVEF, NYHA cardiac function, LVEDV, LVESV, MRA/LAA.Results: (1) Ts-SD and Ts-maxD in 12 LV segments of the DCM patients with chronic heart failure (38.66±12.71ms and 119±30ms, respectively) were significantly higher than that of the healthy controls (22.98±5.59ms and 55±15ms, respectively) (p<0.01).(2) The incidence of LV-SD in DCM patients with chronic heart failure and normal QRS wave width was 29.8% (14/47 cases). However, no case of LV-SD was found in the healthy subjects.(3) 32 patients (68%) had only one delayed systolic, while 15 patients (32%) had two or more wall delayed systolic on LV wall. The site distribution of LV-SD successively was the inferior wall (21/47 cases, 45%), the posterior wall (13/47 cases, 28%), the lateral wall (12/47 cases, 26%), the former interval wall (9/47 cases, 19%), the posterior septum wall (5/47 cases, 11%) and the anterior wall (4/47 cases, 9%).(4) In DCM patients with CHF, the linear regression analysis revealed a negative correlation between Ts-SD, Ts-maxD and LVEF (r=-0.553, -0.560, p<0.001, respectively); but a positive correlation between Ts-SD, Ts-maxD and LVEDV, LVESV (r=0.557, 0.654, 0.629, 0.710, P <0.001, respectively).(5) In DCM patients with CHF, Ts-SD, Ts-maxD exhibited a positive correlation with NYHA cardiac function(r=0.590 and r=0.549, p<0.001, respectively), and with mitral regurgitation (r=0.0.542 and r=0.530,p<0.001, respectively)Conclusion: (1) LV-SD exists in part of DCM patients with normal width of the QRS and chronic heart failure with a incidence of 29.8 %.(2) LV-SD aggravate damage extent of LV systolic function, and closely associate with left ventricular remodeling.(3) LV-SD may be one of the reasons for functional mitral regurgitation with DCM.